Class 10

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 5.3 Water Resources of India offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 5.3 Question Answer – Water Resources of India

Answer in short : 2 Marks

Question 1.
Name the countries through which the river Indus flows.
Answer:
Tibet, Jammu and Kashmir of India, and Pakistan.

Question 2.
Name the five tributaries of river Indus in India.
Answer:
Rivers Jhelum, Chenab, Ravi, Beas, Sutlej.

Question 3.
Name the left bank tributaries of Ganga.
Answer:
Rivers Gomoti, Ghagar, Kosi, Gandak.

Question 4.
Name the right bank tributaries of Ganga.
Answer:
Rivers Yamuna, Son, Damodar, Ajay.

Question 5.
Why is river Kosi called the Sorrow of Bihar ?
Answer:
The river Kosi causes much flood during the rainy season. Hence it is called the ‘Sorrow of Bihar’.

Question 6.
Why are the Himalayan rivers perennial ?
Answer:
The Himalayan rivers get the water supply from snow-melt water throughout the year and rainfall in the rainy season. Hence, they are perennial.

Question 7.
Name some tributaries of the river Brahmaputra.
Answer:
Rivers Subanasiri, Kameng, Manas and Sankosh on the right bank. Rivers Buridihang, Dibang, Kapili and Dhansiri on the left bank.

Question 8.
Mention the course of river Narmada.
Answer:
River Narmada rises from the Amarkantak peak of the Mahakal hills from a spring, flows through a rift valley and finally drains into the gulf of Khambat.

Question 9.
Name two rift valleys of India.
Answer:
The valleys of rivers Narmada and Tapti.

Question 10.
What do you mean by an inland river ?
Answer:
A river which has its source from a moutain or highland, flows through the land and finally drains into a lake or other inland water body, is called an inland river. Eg-River Luni of Rajasthan.

Question 11.
Write about the course of river Godavari.
Answer:
The river Godavari (1,465 km) has its source in the Trimbakeswar in the Western Ghats and drains into the Bay of Bengal. Due to its great length, it is often called the Ganga of the south.

Question 12.
What is a lake?
Answer:
A lake is a depression on the surface of the earth filled with natural water coming from rainfall, snow melt, rivers or underground water.

Question 13.
What is a Kayal or lagoon ?
Answer:
A Kayal or lagoon is a water body surrounded by land on three sides and one side connected to the sea. In many cases, sea water may get arrested by sand bars on three sides and form lagoons or kayals. Eg-Chilka lake in Odisha, Vembanad lake in Kerala.

Question 14.
What is a multi-purpose project ?
Answer:
A multi-purpose project is one in which a river is dammed for various purposes like – irrigation, flood control, generation of hydro-electricity, water transport, fisheries, controlling soil erosion, etc.

Question 15.
Which states of India are mostly irrigated by canals ?
Answer:
The states that are mostly irrigated by canals are – Uttar Pradesh, Punjab, Haryana, Rajasthan, West Bengal, Bihar, Andhra Pradesh, Gujarat, etc.

Question 16.
Which states in India are mostly irrigated by tanks ?
Answer:
Most parts of the peninsular India came under tank irrigation. The states predominated by this are – Tamil Nadu, Karnataka, Andhra Pradesh, Madhya Pradesh, Odisha. Apart from these, some areas of West Bengal, Bihar and Gujarat also practice tank irrigation.

Question 17.
What is the advantage of well irrigation ?
Answer:
Wells can be dug very near the fields, so that water can be provided for cultivation very easily.

Question 18.
What is the disadvantage of well irrigation?
Answer:
Wells cannot be dug where the soil is hard or the land is rocky. It is also not possible in areas where water table is very low.

Question 19.
What are inundation canals ?
Answer:
The inundation canals are those which flow during the rainy season when the rivers are in flood.

Question 20.
What are the advantages of canal irrigation?
Answer:
Canals can be divided into branches for reaching water to fields easily. Sometimes the canals can be used for fishing, navigation or other activites.

Question 21.
What are the disadvantages of canal irrigation?
Answer:
Water level in canals may rise or fall according to availability of water in different seasons. Canals cannot be drawn on hard rocky surfaces or sandy deserts.

Question 22.
What do you mean by rain water harvesting ?
Answer:
Rain water harvesting is the accumulation and storage of rain water to reuse rather than allowing it to run off. Its uses include water for gardening, livestock, irrigation, domestic use, etc. It can also be treated and used as drinking water.

Question 23.
Where does the river Indus rise?
Answer:
The river Indus rises in the springs of Sengge Khabab at an altitude of 5,180 m and about 100 km north of Manas Sarovar.

Question 24.
Name the states through which the tributaries of river Indus flow in India.
Answer:
The tributaries of river Indus flow in India through the states of JammuKashmir, Himachal Pradesh and Punjab.

Question 25.
Where does the river Ganga rise from ? What is it known at the source?
Answer:
The river Ganga rises from the Gomukh cave of Gangotri glacier in the Kumaon Himalayas of Uttarakhand. At the source it is known as river Bhagirathi.

Question 26.
Which is the longest river of India ?
Answer:
The longest river of India is river Ganga. It flows through India for 2,071 km out of the total length of 2,510 km.

Question 27.
Where does the river Yamuna rise?
Answer:
The river Yamuna rises from the Yamunotri glacier of Kumaon Himalayas in Uttarakhand. It meets with river Ganga as a right bank tributary in Allahabad.

Question 28.
Which two rivers meet to form river Ganga ?
Answer:
Rivers Bhagirathi and Alokananda meet at the Dev Prayag to form river Ganga.

Question 29.
Why are the Himalayan rivers called Antecedent rivers ?
Answer:
The Himalayan rivers like Ganga, Indus, Brahmaputra existed even before the emergence of the Himalayan mountains. The rise of the mountains have only changed the courses of the rivers. Thus, these rivers are called antecedent rivers.

Question 30.
Name the states thrugh which river Ganga flows in India.
Answer:
The river Ganga flows through Uttarakhand, Uttar Pradesh, Bihar and West Bengal.

Question 31.
Name the states through which river Brahmaputra flows in India.
Answer:
The river Brahmaputra flows through Arunachal Pradesh and Assam in India.

Question 32.
Name four tributaries of river Narmada.
Answer:

• Hiran
• Barna
• Orsang
• Kolar.

Question 33.
Through which states does the river Narmada flow ?
Answer:
The river Narmada flows through Madhya Pradesh and Gujarat.

Question 34.
Name two west flowing rivers of India.
Answer:
Narmada and Tapti.

Question 35.
On which side of the Satpura range is the river Narmada situated ?
Answer:
River Narmada lies to the north of the Satpura range.

Question 36.
Name a famous waterfall on the river Narmada.
Answer:
Dhuandhar waterfalls near Jabalpur in Madhya Pradesh.

Question 37.
Where does river Tapti rise?
Answer:
River Tapti rises from a hot spring called Multai in the Mahadev hills of Madhya Pradesh.

Question 38.
Name four tributaries of river Tapti.
Answer:

• Purna
• Girna
• Bori
• Bheghar.

Question 39.
Which is the highest waterfall of India ?
Answer:
The highest waterfall is the Jog waterfalls on river Sharavati in Karnataka. It is 275 m high.

Question 40.
Mention the course of river Mahanadi.
Answer:
River Mahanadi rises from the Shihawa hills of Rampur district of Chattisgarh and flows into the Bay of Bengal.

Question 41.
Through which states does river Mahanadi flow ?
Answer:
River Mahanadi flows through Chattisgarh and Odisha.

Question 42.
Name two tributaries of river Mahanadi.
Answer:

• River Brahmani
• River Baitarani

Question 43.
Which is the longest river of South India ?
Answer:
The largest as well as the longest river of South India is the river Godavari.

Question 44.
Where does the river Krishna rise?
Answer:
The river Krishna rises in the hills of Mahabaleswar (1,337 m) in the Western Ghats.

Question 45.
Through which states does the river Krishna flow ?
Answer:
River Krishna flows through Maharashtra, Karnataka, Telengana and Andhra Pradesh before meeting the Bay of Bengal.

Question 46.
Which famous dam is built on river Krishna ?
Answer:
The famous dam built on the river krishna is Nagarjuna Sagar Dam.

Question 47.
Name few tributaries of river Krishna.
Answer:
Some tributaries of river Krishna are river Koyna, Bheema, Tungabhadra, Vedavati, Ghat prabha, Musi, Doodh Ganga etc.

Question 48.
Where does the river Cauvery rise?
Answer:
River Cauvery rises in the Brahmagiri hills (1,341 m) of Coorg district of Karnataka.

Question 49.
Name some tributaries of river Cauvery.
Answer:
Some tributaries of river Cauvery are river Himavati, Bedmati, Amaravati, Lakshmana, Tirtha, Simsa, Bhavani etc.

Question 50.
Name the famous waterfalls on river Cauvery.
Answer:
The famous waterfalls on river Cauvery is the Shivasamudram.

Question 51.
Through which states does the river Cauvery flow ?
Answer:
The river Cauvery flows through Karnataka and Tamil Nadu.

Question 52.
Name two famous lakes of Jammu-Kashmir.
Answer:
Dal Lake and Wular lake.

Question 53.
Name two famous lakes of Uttarakhand.
Answer:
Nainital and Bheemtal.

Question 54.
Name two artificial lakes of India.
Answer:

• Osman Sagar in Telengana.
• Pushkar lake in Ajmer district of Rajasthan.

Question 55.
Name four famous irrigation canals constructed in Uttar Pradesh.
Answer:

1. Upper Ganga canal
2. Lower Ganga canal
3. Sarda canal
4. Yamuna canal.

Question 56.
Name four irrigation canals in Punjab.
Answer:

1. Upper Bari Doab canal
2. Sirhind canal
3. Bhakra canal
4. Bist Doab canal.

Question 57.
Name two irrigation canals of West Bengal.
Answer:

• Damodar canal
• Mayurakshi canal.

Question 58.
Which is the largest canal of India ?
Answer:
The largest canal of India is the Indira Gandhi canal or the Rajasthan canal.

Question 59.
Which is the longest canal of India ?
Answer:
The longest canal of India is the Sarda canal of Uttar Pradesh.

Question 60.
Name two perennial canals of India.
Answer:

• Sarda canal of Uttar Pradesh
• Yamuna canal of Punjab.

Question 61.
Which state in India possesses the maximum irrigated land?
Answer:
The maximum irrigated land lies in Punjab. Here, about 94 % of agricultural land is under irrigation.

Question 62.
Which state has the lowest irrigated land in India ?
Answer:
The lowest irrigated land lies in Jammu-Kashmir (only about 1.3 % of total agricultural land).

Question 63.
Which is the longest dam in India ?
Answer:
The longest river dam in India is the Hirakud dam constructed on the river Mahanadi in Odisha.

Question 64.
Which is the highest dam in India ?
Answer:
The highest dam in India is the Bhakra dam constructed on the river Sutlej in Himachal Pradesh.

Question 65.
Which is the largest multipurpose project in India ?
Answer:
The largest multipurpose project in India is the Bhakra-Nangal project on the river Sutlej.

Question 66.
Where has the ‘Sardar Sarovar Project’ been constructed ?
Answer:
The Sardar Sarovar Project has been constructed on river Narmada in Gujarat.

Question 67.
Name the dams constructed under the Damodar Valley Project.
Answer:
The Damodar Valley Project had a plan of constructing 8 dams. But due to lack of funds, only 4 dams could be constructed. These are :

• Maithan
• Panchet
• Konar
• Tilaiya

Question 68.
Name the hydel power stations under the DVC.
Answer:

1. Panchet
2. Maithan
3. Tilaiya

Question 69.
Name the thermal power stations under the DVC.
Answer:

1. Bokaro
2. Durgapur
3. Chandrapura
4. Wariya

Question 70.
Which states lead in irrigation by wells and tubewells?
Answer:
The states of Uttar Pradesh and Rajasthan lead in irrigation by wells and tubewells.

Answer in brief : 3 Marks

Question 1.
Describe the course of the river Indus.
Answer:
The river Indus rises in the springs of Sengge khabab at an altitude of 5,180 m, about 100 km north of Manas Sarovar. It enters Indian territory in Jammu and Kashmir. It flows through Ladakh, Baltistan and Gilgit to finally emerge at of the hills of Atlock. It flows through India for about 709 km, and then enters Pakistan. The main tributaries of Indus in India are – Jhelum, Chenab, Ravi, Beas, Sutlej.

Question 2.
What do you mean by an ‘ideal river’ ?
Answer:
A river which has three distinct courses, that is the upper course in the hilly region, the middle course in the plateau or highland region and the lower course in the plain region is called an ideal river. Eg-River Ganga.

Question 3.
Describe the upper course of the river Ganga.
Answer:
The river Ganga rises from the Gomukh cave of the Gangotri Glacier in the Himalayas. Here it is known as river Bhagirathi. Sweeping westwards for 35 km from Gomukh, the Bhagirathi turns south and flows for another 140 km through the lesser Himalayas. When the Alokananda, originating from the glacial snout of Alakapuri Glacier joins the Bhagirathi at Dev Prayag, it is called the Ganga. From its source at Gomukh till Haridwar, is the upper course of the river Ganga. From Haridwar to the Raj Mahal hills is the middle course, and from the Raj Mahal hills to the Bay of Bengal is the lower course of the river.

Question 4.
Why are the rivers of south India more speedy than the rivers of north India?
Answer:
The rivers of south India, eg-Godavari, Krishna, Cauvery, Tungabhadra, etc. rise from the hills of the peninsula of India and flow through the plateau region before entering the sea. This plateau is made of igneous rocks, which are very resistant and hard to erode. Also, the rivers flow along the slope of the terraces and hills formed due to lava deposition. There is hardly any presence of plains. Hence, the rivers are very speedy.

Question 5.
Why are the south Indian rivers not perennial like the north Indian rivers?
Answer:
The north Indian rivers rise from the snow-clad mountains of the Himalayas. They get their supply of water from snow-melt as well as heavy orographic rainfall that hit the mountains. Hence, they are perennial. The south Indian rivers rise from the lower hills of the plateau region, which are not snow clad. Hence, they receive water only from rainfall. But rainfall does not occur througout the year. The rivers tend to dry up when there is no supply of rain water. Hence, they are non-perennial.

Question 6.
Why does most of the east flowing rivers form deltas?
Answer:
Most of the east flowing rivers form deltas because :

1. The speed of east flowing rivers is less, hence scope of silt deposition is more.
2. Numerous tributaries of these rivers contribute much silt along with water.
3. The continental shelf on the eastem cost is very gentle, which helps in accumulation of silt.
4. The length of the east flowing rivers is much more. Hence, the amount of eroded material is also quite more and the rate of deposition of these materials is also high.

Question 7.
Write a short note on tubewell irrigation.
Answer:
A tubewell is a deep bore dug into the ground with drilling equipments for drawing out ground water with the help of a pump. Tubewells have proved to be very useful in the alluvial plains of Punjab, Haryana, Uttar Pradesh and Bihar. U.P. has the highest number of tubewells. There are about 31,000 tubewells in the country which irrigate about 60 lakh hectares of bud. About 23 % of total irrigated area in India is served by tubewells.

Question 8.
List the advantages and disadvantages of well and tubewell irrigation.
Answer:
Advantages :

• Less costly, hence poor farmers can also afford.
• Water can be drawn out as per requirement.
• Can be constructed very near to the fields.
• The water drawn from underground is rich in minerals, which make it very useful to make the soil fertile.

Disadvantages :

• This kind of irrigation is usually constructed individually, and not in group.
• This can irrigate only a small area.
• Some wells and tubewells may dry up due to use for many years.
• Dependent of level of water in the undergound reservoir.
• Arsenic contamination may result due to overuse of water.

Question 9.
List the advantages of irrigation.
Answer:
The advantages of irrigation are:

• It helps to increase food production.
• It helps to modify the quality of soil.
• It helps to reduce risk of catastrophic damage by droughts.
• It helps to increase national income.
• It increases labour employment and improves the standard of living.
• It provides with the domestic and industrial water supply.
• Sometimes it is used for generation of hydro-electric power.

Question 10.
What are the disadvantages of irrigation?
Answer:
The disadvantages of irrigation are :

• Water logging.
• Rise in salinity or alkalinity of soil.
• Hampers aeration of soil.
• Pollution of underground water.
• Colder and damper climate indirectly caused by irrigation processes cause out break of diseases like malaria.

Question 11.
Discuss the impacts of overusing ground water.
Answer:
The several impacts for overusing ground water are :
(a) Water table may be lowered due to rapid evaporation and drawing out of water.
(b) Wells, ponds etc. may dry up in warm seasons, or due to overdrawing of water.
(c) Too much extraction of ground water creates a partial vacuum which may lead the land surface to collapse.
(d) Too much drawing of water may lead to droughts and soil damage.
(e) Quality of ground water will gradually deteriorate.
(f) Arsenic contamination may result due to drawing of water at very high rates.

Question 12.
What is a watershed ?
Answer:
The highland that separates two adjacent river catchment areas is called a ‘watershed’. They are important because the flow of water in the catchment area, the speed and volume of water, the amount of silt generated, etc. depend on the nature of the watershed.

Question 13.
Why is tubewell irrigation popular in north India ?
Answer:
Tubewell irrigation is popular in north India because :

1. The lndo-Gangetic plain is composed of soft porous sedimentary rocks which can be dug easily.
2. The porous layers of the rocks allow recharge of groudwater easily, hence water is easily available in tubewells dug in this region.
3. The water table in this region is near the surface, thus it can be acquired by minimum digging.
4. Tubewells are less expensive to construct than canals and other means of irrigation.

Question 14.
What are the advantages of rain water harvesting ?
Answer:
The advantages of rain water harvesting are :

1. It provides an independent water supply during regional water restrictions or droughts.
2. It can mitigate flooding of low lands.
3. It helps to sustain groundwater level.
4. It ensures availability of potable water, clean and free from salinity.
5. It helps to re-use runoff water for gardening, livestock, irrigation, domestic use, etc.

Question 15.
Why are rivers Narmada and Tapti west flowing ?
Answer:
The rivers Narmada and Tapti are west flowing because :

1. The slope of the land over which these rivers flow is from east to west.
2. The Western Ghats do not exist in the region where these rivers flow. Hence, they meet the Gulf of Khambat without any hurdles.
3. These rivers flow through rift valleys. Hence, they have made their way through the narrow valleys along the fault lines very easily.

Question 16.
Why don’t the west-flowing rivers form deltas before meeting the sea?
Answer:
The west-flowing rivers of India, i.e. Narmada and Tapti do not form deltas at their mouths because :

1. Length : The rivers flow for a short length and do not have enough water or amount of load. (Narmada – 1312 km, Tapti – 928 km)
2. Tributaries : These rivers have a very few tributaries. Hence, contribution of load is also very less.
3. Type of rock : The rivers flow over hard rocky surface. Hence, amount of eroded material is small.
4. Speed : The rivers flow with great speed, thus removing and discarding all the load far away from the mouths.
5. Continental shelf: The continental shelf in the region where the rivers meet the Gulf of Khambat is quite steep. Thus, accumulation of silt to form deltas is difficult.

Question 17.
Differentiate between Wells and Tubewells.
Answer:

Wells	Tubewells
i. Wells are dug in soft soil and water is pulled out by hand or with the help of animals.	i. Tubewells are constructed by inserting metal or nylon pipes in soft soil and pulling out water by pumps.
ii. Help to pull out water from shallow levels.	ii. Help to pull out water from deep levels.
iii. No requirement of electric or other power resources.	iii. Cannot work without using power from petrol, diesel, electricity etc.
iv. Radius of well is large.	iv. Radius of pipeline is very small.
v. The mouth of the well remains open.	v. The mouth of the pipe remains in the pump.

Question 18.
Mention the states where canal irrigation is predominant.
Answer:
Canal irrigation is predominant in – Uttar Pradesh, Punjab, Haryana, Rajasthan, West Bengal, Bihar, Andhra Pradesh, Gujarat etc.

Question 19.
Differentiate between inundation canals and perennial canals.
Answer:

Inundation canals	Perennial canals
i. In rainy season, the excess water of the rivers is diverted for imigation and other works through canals.	i. Water from perennial rivers is used for irrigation and other purposes throughout the year.
ii. Usually usable in rainy season and remain dry in dry season.	ii. Usually usable in all seasons throughout the year.
iii. Usually seen in flood-prone areas.	iii. Usually seen in areas where perennial rivers flow.
iv. Usually constructed in the delta regions or lower courses of rivers.	iv. Usually constructed in the middle course or the plain lands of a river.
v. Helps in flood control.	v. No remarkable influence in flood control.

Question 20.
What is a Multi-purpose river project? What are its aims?
Answer:
A project on a river that is planned for economic and social development of a place by using the water of the river for multiple purposes, is called a multipurpose project.
Aims – The different aims of a multi-purpose project are – (i) Irrigation, (ii) Production of hydro-electric power, (iii) Flood control, (iv) Navigation and water transport, (v) Supply of drinking water, (vi) Pisciculture, (vii) Building of bridges, (viii) Construction of roadways and railways, (ix) Scope of employment to a huge population, (\mathrm{x) Control of soil erosion, (xi) Development of tourist spots, (xii) Afforestation, (xiii) Development of new settlements.

Answer in details : 5 Marks

Question 1.
Describe the course of river Ganga.
Answer:
Ganga is the main and longest river of India. Its total length is 2,510 km, of which 2,071 km flows through India.

Upper course : The river Ganga rises from the glacial snout Gomukh of the Gangotri glacier. It is then called Bhagirathi. It meets with river Alokananda at the Dev Prayag, after which the river comes to be known as the Ganga. The upper course of Ganga extends from Gomukh to Haridwar for about 320 km. Middle course : It stretches from Haridwar to Dhulian in West Bengal. The left bank tributaries are Ram Ganga, Gomoti, Ghaghra, Gandak, Kosi, etc. The right bank tributaries are – Yamuna and Son. Yamuna is the largest and most important tributary of the Ganga.

Lower course : The lower course extends from Dhulian in Murshidabad (WB) to the Bay of Bengal. The river divides into two branches near Giriya district of Mushidabad as Bhagirathi and Padma. The Padma enters Bangladesh and meets the Bay of Bengal from there. The Bhagirathi flows southwards through West Bengal as Hooghly river. The main left bank tributaries are – Jalangi, Ichhamati, Churni, etc. The right bank tributaries are – Brahmani, Dwarka, Ajay, Mayurakshi, Damodar, Rupnarayan, Kangsabati, etc. The Bhagirathi Hooghly, along with the Padma, form the world’s largest delta before meeting the Bay of Bengal.

Question 2.
Describe the course of river Brahmaputra.
Answer:
The Brahmaputra river is 2700 km long, of which 885 km flows through India. It rises from the Chemayundung glacier, south west of Manas Sarovar. It flows eastward through Tibet where it is known as Tsang-Po. After taking a sharp bend towards the south, it enters India through a deep gorge in the east of Namcha Barwa in Arunachal Pradesh as Dihang. The river Dihang meets with rivers Dibang and Lohit and then flow as a single river called Brahmaputra. It flows through Assam from the east near Sadiya to the west upto Dhubri and then takes a sharp turn towards the south and enters Bangladesh as river Yamuna. The important right bank tributaries are-Subansiri, Barali, Manas, Teesta, etc. The left bank tributaries are – Buri, Dihing, South Dhansiri, etc.

Question 3.
Discuss the importances of lakes, canals and reservoirs in human life.
Answer:
The importances of lakes, canals and reservoirs in human life are –
i. Irrigation : Lake water can be used for irrigation and make cultivation possible in adjacent areas.

ii. Flood control : Lakes and reservoirs help to hold the excess runoff from rain water and help to control floods.
iii. Fishing : The water bodies help in cultivation of fish and ensure supply of protein based food to the locality as well as outside.
iv. Transport : Large lakes may act as a mode of transport by boats and steamers.
v. Tourism : Beautiful scenery and pleasant weather near lakes and resevoirs attract many tourists, thus gain econonic importance as tourist spots.

Question 4.
What is the impact of overuse of ground water?
Answer:
The biggest reservoir of fresh water on earth is ‘ground water’ which holds more than 20 times of total surface water (lakes, rivers, ponds, etc.). Ground water is pumped out to meet agricultural, industrial and domestic depends. But overuse of ground water may cause several problems –

1. Lowering of water table.
2. Drying up of wells, ponds, etc.
3. Subsidence and collapse of land surface.
4. Drought and damaged soil.
5. Deterioration of water quality.

In India, over 16 % of ground water resources are over exploited, mainly in north western, western and peninsular regions. If this trend continues, 60 % of India’s acquifers will be in critical condiions in coming 20 years.

Question 5.
Write a short note on the Damoder Valley Project.
Answer:
The Damodar Valley Project is the first Multi-purpose project in independent India. It was started in 1948. It was based on the Tennessee Valley Project of USA. The Damodar Valley Corporation (DVC) has been developed on river Damodar in Jharkhand and West Bengal. It consists of a series of dam on this river and its tributaries. The river Damodar rising in the chotanagpur plateau region, fluctuates in water level too much. In the rainy season it causes dreadful floods destroying life and property. Hence, it is known as the ‘Sorrow of Jharkhand (Bihar)’.

The DVC has constructed multi-purpose dams at Tilaiya (on river Barakar), Konar (on river Konar), Maithon (on river Barakar) and Panchet (on river Damodar). Hydel power stations have been constructed at Maithan, Tilaiya and Panchet. The 672 m long and 11.58 m deep barrage on the river Damodar at Durgapur, 226 km long irrigation canals help to irrigate about 5 lakh hectares of land. The thermal power stations at Bokaro, Chandrapura, and Durgapur produce about 1,081 MW of electricity. The DVC has now handed over its overall control to the Govt. of West Bengal.

Question 6.
What is Watershed management?
Answer:
Watershed management refers to the scientific use and utilisation of water recources to stop soil erosion, increase soil fertility, control floods, prevent siltation of river beds and maintain proper land use patterns. The various methods that are used in watershed management are –
i. Slope management : The higher slopes of the river basin that are prone to land slides and soil erosion can be taken care of by planting trees, grasslands, stopping jhum cultivation. Guard walls can be built in some cases to protect the land.
ii. Flood control : Floods can be controlled by dredging of rivers, ponds, lakes etc and increasing their water holding capacities.
iii. Gully erosion : Gully erosion and sheet erosion can be controlled by planting trees across the flow of runoff and building small dams at places.
iv. Contour farmıng : Contour farming, terrace farming etc. can help to stop soil erosion and increase water seepage to increase the ground water level.
v. Multi-purpose projects : Multi-purpose projects can be planned for purposes like irrigation, hydel power, fish culture, flood control, water transport, control of soil erosion, tourism, etc.

Question 7.
Discuss about rain water harvesting in Tamil Nadu.
Answer:
Rain water harvesting is the accumulation and storage of rain water for reuse, rather than allowing it to run off. Its uses include water for gardening, livestock, irrigation, domestic use, etc. It can also be used as drinking water.

Tamil Nadu : Tamil Nadu receives rainfall twice a year. Hence, it is the best region for rain water harvesting. In order to augment ground water resourses, it has been made mandatory in Tamil Nadu to provide rain water harvesting structures in all buildings. The arrangement is such deviced that after the first rain washes away the dirt and dust of the roofs, water can be collected and stored. Different type of devices are used for different types of roofs. Presently, 40 % of rain water is being stored underground. In Chennai alone, a 150 \mathrm{sq . \mathrm{km underground water reservoir meets the scarcity of water.

Question 8.
Describe canal irrigation system in India.
Answer:
The method of irrigation by digging canals from rivers towards agricultural fields through the soft silty soil is known as canal irrigation. Canal irrigation is popular in plains where the slope of land is moderate.
Areas – The areas under canal irrigation in India are Punjab, Uttar Pradesh, Delta regions of rivers, etc.
Types – Canals are usually of two types –
(i) Perennial canals – Which have water throughout the year as they are dug from perennial rivers.
(ii) Inundation canals – Which receive water when the rivers are in flood in rainy season.
Amount of canal irrigation – About 50 % of canals are spread over Uttar Pradesh, Punjab, Haryana, West Bengal and Andhra Pradesh. About 38 % of agricultural land is irrigated by canals.

Question 9.
What is rain water harvesting ? What are the different methods of rain water harvesting ?
Answer:
The process of collecting rain water from roof tops and other open places for reuse for different purposes is called rain water harvesting.
The different methods of rain water harvesting are –
i. Construction of tanks – Rain water can be collected in natural or artificial tanks, ponds, lakes, etc. in the rainy season and can be used later in the dry season.

ii. Construction of Small dams – Higher dams disrupt the natural flow of water in the rivers to a great extent. This may cause many adverse effects. But construction of small and low dams to stop the flowing water only by portions may come out to be a very useful method of rain water harvest.

iii. Collection of rain water – Rain water can be collected from roof tops and other open surfaces or areas which receive heavy rainfall from the monsoons.

iv. Proper use of ground water – The ground water utilisation may be improved from 35-40 % to 60 % by implementing proper methods of acquiring the ground water. Unplanned water acquiring processes must be prevented with the help of rules and regulations.

v. Ground water recharge – Scope must be given for percolation of rain water into the soil for recharge of underground water. In some cases, there may be the need for recharging ground water artificially.

Multiple Choice Questions (MCQ) : 1 Mark

Question 1.
Which of the following is a Trans-Himalayan river?
(A) Ganga
(B) Yamuna
(C) Sutlej
(D) Ravi
Answer:
(C) Sutlej

Question 2.
Which of the following rivers is not a tributary of Ganga ?
(A) Gomati
(B) Gandak
(C) Kosi
(D) Ghagra
Answer:
(D) Ghagra

Question 3.
Which of the following rivers lies in a rift valley ?
(A) Luni
(B) Chambal
(C) Sone
(D) Tapti
Answer:
(D) Tapti

Question 4.
Narmada originates from its source situated in the state of :
(A) Maharashtra
(B) Uttar Pradesh
(C) Madhya Pradesh
(D) Andhra Pradesh
Answer:
(C) Madhya Pradesh

Question 5.
The Jog falls are situated on the :
(A) Tapti river
(B) Sharavati river
(C) Cauvery river
(D) Bhima river
Answer:
(B) Sharavati river

Question 6.
Why is the Delta of the Indus small compared to the Delta of the Ganga?
(A) The Indus traverses a shorter distance than the Ganga
(B) The Indus is not as broad as the Ganga
(C) The path of the Indus is through arid area while the Ganga collects more water along its path to the sea
(D) None of the above
Answer:
(C) The path of the Indus is through arid area while the Ganga collects more water along its path to the sea

Question 7.
The Indian rivers of the Indus Basin are :
(A) Sutlej, Beas and Ravi
(B) Ganga, Beas and Sutlej
(C) Betwa, Sone and Kosi
(D) Gomati, Kosi, Gandak
Answer:
(A) Sutlej, Beas and Ravi

Question 8.
Beas flows through the State of –
(A) Punjab, Haryana and Rajasthan
(B) Punjab, Haryana and Jammu
(C) Punjab and Himachal Pradesh
(D) Punjab and Haryana
Answer:
(D) Punjab and Haryana

Question 9.
River Cauveri flows through the States of-
(A) Madhya Pradesh, Maharashtra and Tamil Nadu
(B) Karnataka, Kerala and Tamil Nadu
(C) Madhya Pradesh, Gujarat and Tamil Nadu
(D) Kerala, Karnataka and Andhra Pradesh
Answer:
(B) Karnataka, Kerala and Tamil Nadu

Question 10.
Ganga beyond Farakka, when it enters Bangladesh, is known as :
(A) Padma
(B) Meghna
(C) Hooghly
(D) Swaran Ganga
Answer:
(A) Padma

Question 11.
Which of the following has almost the same point of beginning ?
(A) Ganga and Indus
(B) Ganga and Brahmaputra
(C) Beas and Tapti
(D) Indus and Brahmaputra
Answer:
(D) Indus and Brahmaputra

Question 12.
The river that flows between the Vindya and the Satpura Mountain is :
(A) Maki
(B) Narmada
(C) Tapti
(D) Sharavati
Answer:
(B) Narmada

Question 13.
The Alakananda and the Bhagirathi meet at :
(A) Prayag
(B) Devaprayag
(C) Haridwar
(D) Rishikesh
Answer:
(B) Devaprayag

Question 14.
The left bank tributary of the Ganga is the :
(A) Sone
(B) Gomati
(C) Yamuna
(D) Damodar
Answer:
(B) Gomati

Question 15.
The river Chambal flows into the :
(A) Tapi
(B) Ganga
(C) Yamuna
(D) Narmada
Answer:
(C) Yamuna

Question 16.
The name “The Gift of the Indus” is given to :
(A) U.P
(B) Gujarat
(C) Sindh
(D) Rajasthan
Answer:
(C) Sindh

Question 17.
Tapti flows into the :
(A) Arabian sea
(B) Cambay Gulf
(C) Gulf of Kutch
(D) All of these
Answer:
(B) Cambay Gulf

Question 18.
The town situated at the mouth of the river Tapti is :
(A) Surat
(B) Broach
(C) Honnavar
(D) Joypur
Answer:
(A) Surat

Question 19.
Jog Falls is across the river:
(A) Sharavati
(B) Cauvery
(C) Krishna
(D) Godavari
Answer:
(A) Sharavati

Question 20.
The source of Godavari is :
(A) Amarkantak
(B) Triambak
(C) Mahabaleswar
(D) Nasik
Answer:
(B) Triambak

Question 21.
Machalipatnam is located at the mouth of :
(A) Tapi
(B) Cauvery
(C) Krishna
(D) Godavari
Answer:
(C) Krishna

Question 22.
The main tributary of the Cauvery is the :
(A) Parna
(B) Vennan
(C) Vettar
(D) Coleroom
Answer:
(D) Coleroom

Question 23.
Porunai is another name of the :
(A) Ganga
(B) Cauvery
(C) Vaighi
(D) Tamiraparani
Answer:
(D) Tamiraparani

Question 24.
The Vaigai river rises in the :
(A) Coorg
(B) Agastiya Hills
(C) Cardamom Hills
(D) Anaimudi
Answer:
(C) Cardamom Hills

Question 25.
The dam across Periyar is at :
(A) Amaravati
(B) Thekkady
(C) Palani
(D) Krishna
Answer:
(B) Thekkady

Question 26.
Tungabhadra flows into the river:
(A) Godavari
(B) Cauvery
(C) Palani
(D) Krishna
Answer:
(D) Krishna

Question 27.
Important west flowing river is :
(A) Mahanadi
(B) Cauvery
(C) Krishna
(D) Narmada
Answer:
(D) Narmada

Question 28.
Bhakra-Nangal is a …… project.
(A) multipurpose
(B) power
(C) irrigation
(D) none
Answer:
(A) multipurpose

Question 29.
Mettur is the most important multipurpose project for the state of :
(A) Kerala
(B) Karnataka
(C) Andhra Pradesh
(D) Tamil Nadu
Answer:
(D) Tamil Nadu

Question 30.
Kosi Project is a joint venture of :
(A) India and Bangladesh
(B) India and Nepal
(C) India and Bhutan
(D) Bhutan and Nepal
Answer:
(B) India and Nepal

Question 31.
Sivasamudram fall is across river :
(A) Godavari
(B) Krishna
(C) Sharavati
(D) Cauvery
Answer:
(D) Cauvery

Question 32.
The Ganga enters the great plains at :
(A) Agra
(B) Allahabad
(C) Patna
(D) Haridwar
Answer:
(D) Haridwar

Question 33.
The peninsular rivers have their source in the :
(A) Satpura
(B) Western Ghats
(C) Himalayas
(D) Bay of Bengal
Answer:
(B) Western Ghats

Question 34.
The most important tributary of the Ganga is :
(A) Tapti
(B) Yamuna
(C) Periyar
(D) None of these
Answer:
(B) Yamuna

Question 35.
The rivers Narmada and Tapti flow into the Gulf of :
(A) Bay of Bengal
(B) Kutch
(C) Mannar
(D) Khambhat
Answer:
(D) Khambhat

Question 36.
The Yamuna joins the Ganga at :
(A) Delhi
(B) Haridwar
(C) Allahabad
(D) Calcutta
Answer:
(C) Allahabad

Question 37.
The northern channel of Cauvery is called :
(A) Hemavathi
(B) Coleroom
(C) Bhavani
(D) Son
Answer:
(B) Coleroom

Question 38.
The river Krishna enters the Bay of Bengal near :
(A) Hyderabad
(B) Vijayawada
(C) Masulipatnam
(D) Nellore
Answer:
(B) Vijayawada

Question 39.
The biggest artificial reservoir is :
(A) Nijam Sagar
(B) Govind Vallab Pant Sagar
(C) Stanley Reservoir
(D) Govind Sagar Lake
Answer:
(B) Govind Vallab Pant Sagar

Question 40.
Rihand Project is mainly a ….. project :
(A) Drinking
(B) Irrigation
(C) Power
(D) Multipurpose
Answer:
(D) Multipurpose

Question 41.
This flows through a rift valley :
(A) Ganga
(B) Mahanadi
(C) Tapti
(D) Luni
Answer:
(C) Tapti

Question 42.
A dam is located at Sambalpur on the Mahanadi river :
(A) Damodar
(B) Bhakra
(C) Hirakud
(D) Nagarjuna Sagar
Answer:
(C) Hirakud

Question 43.
River Damodar is a tributary of :
(A) Yamuna
(B) Sabarmati
(C) Ganga
(D) Ajoy
Answer:
(C) Ganga

Fill in the blanks : 1 Mark

1. The Ganga river comes from the Gangotri glacier which is located at a height of ________ m. in the north of the Kedarnath peak.
2. The river Ganga carries about ________ of the water of the total drainage of India.
3. The river ganga meets river ________ near Gaalundo.
4. Most of the drainage of Himalayas is ________ .
5. The river Gomti meets the river Ganga near ________ .
6. The river ________ flows in India, Bangladesh and Tibet.
7. The ________ waterfalls lie in the upper course of the river Narmada.
8. The ________ lake in India has the highest salinity.
9. The river Brahmaputra is known as ________ in Tibet.
10. The river ________ changes its course frequently
Answer:
1. 6600
2. 25 %
3. Brahmaputra
4. Antecedent
5. Gazipur
6. Brahmaputra
7. Kapil dhara
8. Sambhar
9. Tsang po
10. Kosi

State True or False : 1 Mark

1. About 15 % of the agricultural fields in India are irrigated with the help of wells. [ ]
2. Rajasthan ranks first in India in well and tube well irrigation. [ ]
3. The Bhakra-Nangal multipurpose project has been constructed on the river Krishna. [ ]
4. The Hirakud dam has been constructed on the river Mahanadi. [ ]
5. The Bhakra-Nangal project is the longest multipurpose project of India [ ]
6. The Koleru lake is the largest sweet water lake in India. [ ]
7. The Pangong lake is the highest lake of the world. [ ]
8. The largest lake of western India is the Loktak lake. [ ]
9. Pulicat lake is the largest lake of Kerala. [ ]
10. The Wular lake is a salt water lake. [ ]
Answer:
1. True
2. False
3. False
4. True
5. True
6. True
7. True
8. False
9. False
10. False

Match the following : 1 Mark

List I (Rivers)	List II (Tributaries)
A. Indus	1. Mahananda
B. Ganga	2. Bhima
C. Krishna	3. Wainganga
D. Godavari	4. Nubra

Answer:

List I (Rivers)	List II (Tributaries)
A. Indus	4. Nubra
B. Ganga	1. Mahananda
C. Krishna	2. Bhima
D. Godavari	3. Wainganga

Answer in few words : 1 Mark

Question 1.
Where does the river Indus rise?
Answer:
From the springs of Sengge Khabab, 5,180m high, 100 km north of Manas Sarovar.

Question 2.
Name some Himalayan tributaries of Indus.
Answer:
Gantang, Zaskar, Dras, Shyok, Shigar, etc.

Question 3.
Where does the river Sutlej rise?
Answer:
In lake Rakas in Tibet, 4,555 m high.

Question 4.
Where does the river Beas rise?
Ins.
Beas kend near Rohtang Pass at an elevation of 4,361 m.

Question 5.
Where does the river Ravi rise?
Answer:
From the Kulu hills near Rohtang pass.

Question 6.
How does the river Chenab rise?
Answer:
Formed by union of two streams, the Chandra and the Bhaga.

Question 7.
Where does the river Jhelum rise?
Answer:
From a spring at Verinag in the south-eastern part of the vale of Srinagar.

Question 8.
How muh area does the Ganga basin cover of the total land surface of India?
Answer:
25 %

Question 9.
Where does the river Ganga rise ?
Answer:
Gomukh cave of Gangotri glacier.

Question 10.
What is the source of river Alakananda?
Answer:
Alakapuri Glacier.

Question 11.
Which two rivers meet at Devaprayag ?
Answer:
Alakanada and Bhagirathi, forming river Ganga.

Question 12.
Which two rivers meet at the Rudraprayag ?
Answer:
Alakananda and Mandakini.

Question 13.
How far does the upper course of Ganga extend?
Answer:
Gangotri glacier to Haridwar.

Question 14.
How far does the middle course of Ganga extend?
Answer:
Haridwar to Raj Mahal hills.

Question 15.
How far does the lower course of Ganga extend?
Answer:
Raj Mahal hills to the Bay of Bengal.

Question 16.
Name an ideal river of India.
Answer:
River Ganga.

Question 17.
Name the largest tributary of river Ganga.
Answer:
River Yamuna.

Question 18.
Where does river Yamuna rise ?
Answer:
Yamunotri glacier.

Question 19.
Where does river Yamuna meet river Ganga ?
Answer:
At Sangam in Allahabad.

Question 20.
Name some tributaries of Yamuna on the right bank.
Answer:
Chambal, Sindh, Betwa, Ken.

Question 21.
Where does river Kosi rise?
Answer:
From the Tibet plateau.

Question 22.
Which river is called the Sorrow of Bihar?
Answer:
River Kosi.

Question 23.
Where is the source of river Brahmaputra ?
Answer:
Chemayundung glacier south-west of Manas Sarovar.

Question 24.
What is river Brahmaputra known as in Tibet ?
Answer:
River Tsangpo.

Question 25.
Which two rivers meet to form river Brahmaputra.
Answer:
Rivers Dihang and Dibang.

Question 26.
Name an inland river of India.
Answer:
River Luni of Rajasthan.

Question 27.
Name the west flowing rivers of peninsular India.
Answer:
Rivers Narmada and Tapti.

Question 28.
Where does river Narmada rise from ?
Answer:
Amarkantak Peak of the Mahakal Range.

Question 29.
Where does river Tapti rise from?
Answer:
Mahadeo hills.

Question 30.
Where does the river Tapti drain its water finally?
Answer:
Gulf of Khambat.

Question 31.
Where is the source of river Mahanadi ?
Answer:
Near Amarkantak Peak of the Mahakal range.

Question 32.
Name the main tributaries of river Mahanadi.
Answer:
Rivers Brahmani and Baitarani.

Question 33.
Name the longest river of peninsular India.
Answer:
River Godavari.

Question 34.
What is river Godavari also known as ?
Answer:
The Ganga of the south.

Question 35.
Where is the source of river Krishna?
Answer:
Mahabaleshwar hills.

Question 36.
Name the major tributaries of river Krishna.
Answer:
Rivers Bhima and Tungabhadra.

Question 37.
Where is the source of river Cauvery ?
Answer:
Brahmagiri hills of Westem Ghats.

Question 38.
Name the main tributaries of river Cauvery.
Answer:
Rivers Himavati, Bhavani, Bedavati, Shimsa.

Question 39.
Name the famous waterfalls on river Cauvery.
Answer:
Shivasamudram.

Question 40.
Name 2 kayals or lakes of Kerala.
Answer:
Vembanad (largest) and Ashtamudi.

Question 41.
Name 2 lakes of Jammu and Kashmir.
Answer:
Dal lake, Wular lake.

Question 42.
Name 2 lakes of Uttarakhand.
Answer:
Bheemtal and Nainital.

Question 43.
Name 2 artificial lakes of India.
Answer:
Osman Sagar of Telengana, Puskar lakes of Rajasthan.

Question 44.
Name two irrigation canals of West Bengal.
Answer:
Damodar canal, Mayurakshee canal.

Question 45.
Name the largest irrigation canal of India.
Answer:
The Indira Gandhi canal or the Rajasthan canal.

Question 46.
Which is the longest canal of India ?
Answer:
Sharada canal of Uttar Pradesh.

Question 47.
Name an inundation canal of India.
Answer:
Hijli canal of West Bengal.

Question 48.
Name two perennial canals of India.
Answer:
Sharada canal of UP, Damodor canal of West Bengal.

Question 49.
Which state of India is maximum irrigated ?
Answer:
Punjab (about 94 % of cultivated land).

Question 50.
Which is the longest river dam of India ?
Answer:
Hirakud dam on river Mahandi in Odisha.

Question 51.
Name the highest dam of India.
Answer:
Bhakra Nangal dam on river Sutlej in Punjab.

Question 52.
Name the largest multipurpose project of India.
Answer:
Bhakra-Nangal Project.

Question 53.
Where is the ‘Sardar Sarovar Project’ located ?
Answer:
On river Narmada in Gujarat.

Question 54.
Name the dams under Damodar Valley Corporation.
Answer:

1. Mythan
2. Panchet
3. Konar
4. Tilaiya.

Question 55.
Which state ranks first in use of wells and tubewells for irrigation?
Answer:
Uttar Pradesh.

Question 56.
Which state ranks first in rain water harvesting ?
Answer:
Tamil Nadu.

Question 57.
Which region is apt for digging wells for irrigation?
Answer:
Regions with soft soil and ample of ground water.

Question 58.
How much area is under canal irrigation in India ?
Answer:
45 % of total irrigated area.

Question 59.
On which river is the Mythan dam constructed?
Answer:
River Barakar.

Question 60.
On which river is the Panchet dam constructed?
Answer:
River Damodar.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 5.2 Physiography of India offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 5.2 Question Answer – Physiography of India

Answer in short : 2 Marks

Question 1.
What is the east west extention of the Himalaya.
Answer:
The Himalayas extent from Nanga Parbat in Jammu Kashmir in the West to the Namcha Barwa of Arunachal Pradesh in the east.

Question 2.
Name some famous peaks of the Himalayas.
Answer:
Mt. Everest ( 8,848 m), Kanchenjunga (8,598 m) Dhaulagiri (8,172 m), Nanga Parbat (8,126 m), Annapurna (8,076 m), Nandadevi (7,817 m) etc.

Question 3.
What are ‘doons’?
Answer:
Broad longitudinal valleys lying between the main Himalayas and the Shiwalik range formed by deposition of materials brought down by Himalayan rivers, are called ‘doons’. Eg- Dehradun.

Question 4.
What is the Deccan Trap?
Answer:
The Deccan plateau which is composed of sheets of lava forming basalt rocks descends from west to east like stairs step by step, near the Maharashtra plateau. This region is called the Deccan Trap. [Trap = ‘Steps’ in Swedish]

Question 5.
What is the Rann of Kachch ?
Answer:
The western coastal region spreading through the Kutch peninsula of Gujarat is a low marshy land full of salt deposition due to submergence into the adjacent sea. This region is known as the Rann of Kutch. The northern part is known as the Greater Rann and the southern part is known as the Lesser or Smaller Rann. A few hillocks and isolated rocks can be seen in the Rann of Kutch.

Question 6.
Write a short note on the Western Himalaya.
Answer:
The Western Himalaya lie to the extreme west of the chain of the Himalayan mountains. They are further subdivided into – (i) The North Kashmir Himalaya. (ii) The South Kashmir Himalaya, (iii) The Himachal Himalaya, (iv) The Uttaranchal Himalaya. The Kashmir Himalaya is further divided into the Ladakh range, Zanskar range and the Pir Panjal range. Ladakh is the highest plateau of the world, that lies within these ranges. The important mountain passes present here are – Zojila pass between Srinagar and Leh, and Shipki-la on the Indo-China border.

Question 7.
Write the extent of the northern plains of India.
Answer:

The northern plains of India lie to the south of the Himalayas. It extends from the eastern Rajasthan plains in the west to the Brahmaputra valley in the east for a distance of about 2,500 km. They are 145-480 km broad. They are also known as The Great Northern Plains.

Question 8.
Describe the Punjab-Haryana Plains of the Indus basin.
Answer:
The Punjab-Haryana Plains of the Indus basin are drained by the tributaries of river Indus, i.e. Ravi, Beas and Sutlej. These are flat plains with an average elevation of 200-240 m. These fertile plains include the Bari Doab (between Ravi and Beas rivers) and Bisht Doab (between Beas and Sutlej rivers)

Question 9.
What is Khadar?
Answer:
The lowlands formed in the lower course of the river Ganga and its tributaries, by the deposition of detritus of new alluvium in the river beds and adjacent areas is called Khadar.

Question 10.
What is Bhangar?
Answer:
The uplands formed on the western side of the Ganga plains due to deposition of older alluvium which are coarse and grannular, is known as Bhangar.

Question 11.
What is Malnad?
Answer:
The Western part of the Karnataka plateau which is 320 km long and 35 km wide, is highly dissected and have deeply cut valleys. This region is known as the Malnad.

Question 12.
What is Maidan?
Answer:
The eastern part of the karnataka plateau is formed of rolling plains with low granite hills. This region is known as the Maidan.

Question 13.
Name the important passes in the Western Ghats.
Answer:
The important passes in the Western Ghats are: Thal Ghat, Bhor Ghat and Pal Ghat.

Question 14.
Describe the Eastern Ghats.
Answer:
The Eastern Ghats form the eastern edge of the Deccan Plateau. They are lower in height than the Western Ghats. The Mahendragiri (1,501 m) in Odisha is the highest peak of these hills. The Eastern Ghats have been highly eroded by rivers flowing towards the Bay of Bengal and have been lowered to plains.

Question 15.
Classify the Western Coastal Plains.
Answer:
The Western Coastal Plain is divided into several parts – it is known as the Konkan Coast in Maharashtra, the Karnataka Coast in Karnataka and the Malabar Coast in Kerala. The Gujarat plain is the broadest part of the western coastal plains.

Question 16.
Write about the islands of India.
Answer:
There are two major groups of islands in India. (a) The Andaman and Nicobar Islands : They are located in the Bay of Bengal. They are a group of 324 islands. Saddle Peak (750 m) in North Andaman is the highest peak in this region. Barren island is the only active volcano of India. (b) Lakshadweep : This is a group of islands in the Arabian sea, mainly made up of coral depositions.

Question 17.
Why is India called a miniature edition of the world ?
Answer:
India is a large continent with a great variety in topography. Almost all kinds of relief regions are found here. Numerous type of climates are also found here. There is a great variety of cultural traits as well. Thus, it is rightly called a miniature edition of the world.

Question 18.
Where is the Ladakh plateau located?
Answer:
The Ladakh plateau lies to the North-East of the Ladakh range (between the rivers Indus and Sayak). This is the highest plateau of India.

Question 19.
How can the Himalaya be divided according to its breadth ?
Answer:
The Himalaya is divided according to its breadth from south to north(i) Siwalik (ii) Himachal (iii) Himadri (iv) Tethys.

Question 20.
What is the Siwalik?
Answer:
The Siwalik is the southernmost range of the Himalaya. This is made up of smaller mountains running from west to east. It is 2400 km long and 10-15 km wide.

Question 21.
How is the Himalaya classified along its length ?
Answer:
Along its length, the Himalaya is classified as – (i) Western Himalaya (ii) Central Himalaya (iii) Eastern Himalaya.

Question 22.
Write a short note on the Kashmir valley.
Answer:
The Kashmir Valley lies in Kashmir. It is 150 km long, 80 km wide and covers an area of 4,865 sq . km. This valley comprises great snow clad mountains, the Dal and Wular lakes and tremendous scenic beauty. The valley has depositions of materials brought down by river and glacial erosion. These silt depositions are locally known as Karewa, and are famous for saffron cultivation. The river Jhelum flows through the Karewa.

Question 23.
What do you mean by the Syntaxial bend of the Himalaya ?
Answer:
The chain of Himalayan mountains run East-West in general. But they seem to take bends drastically at the western and eastern corners and turn southwards. These bends are known as the Syntaxial bends. The western syntaxial bend lies near the deep gorge created by river Indus near the Nanga Parvat. The eastern syntaxial bend lies in Arunachal Pradesh, where the mountains take a hair-pin turn after crossing the river Brahmaputra.

Question 24.
Write a short note on the Meghalaya plateau.
Answer:
The Meghalaya plateau comprises the Garo, Khasi, Jayantia and Mikir hilly regions of Meghalaya. It is also known as the Shillong plateau. It is actually a part of the Chotanagpur plateau. In historic times, a huge portion of the huge plateau region subsided and resulted in the formation of the dissected plateau of Meghalaya.

Question 25.
What is a ‘Dhrian’?
Answer:
In Rajasthan, the moving sand dunes of the Thar desert are called ‘Dhrians’.

Question 26.
What is a ‘Dhand’?
Answer:
In Rajasthan, in the Thar desert, the huge and deep hollows or depressions created by deflation of sand by wind, are called ‘Dhands’. These are also called the dry lakes.

Question 27.
What is a ‘Thali’?
Answer:
In the Thar desert in Rajasthan, the fixed or immobile sand dunes are called ‘Thalis’.

Question 28.
What is a Kayal ?
Answer:
In the Malabar coast, due to numerous earth movements, land has been submerged and raised above sea level for a number of times. This has led to the formation of several low-lying regions that remain submerged in sea water. These are called backwaters, lagoons or Kayals. The Vembanad Kayal is the largest Kayal in India.

Question 29.
What is the ‘Bagri’ ?
Answer:
‘Bagri’ is the dead part of the delta of river Ganga, where no silt deposition is currently taking place. It comprises the districts of Nadia and Murshidabad (except Kandi sub-division).

Question 30.
What is ‘Diyara’?
Answer:
‘Diyara’ is the region of new silt deposition in the district of Malda. This is a part of the Ganga delta. It lies in the southern part of the river Kalindi in Malda.

Question 31.
Name some glaciers of the Karakoram range.
Answer:
Some important glaciers of the Karakoram range are – Siachen, Baltora, Rimo etc. Siachen is the longest glacier of India. (76 km.)

Question 32.
How far does the Himalayan range stretch from west to east ?
Answer:
The Himalayan range stretches from Nanga Parvat in Kashmir in the west to Namcha Barwa in Arunachal Pradesh in the east.

Question 33.
Where is the Ladakh range situated ?
Answer:
The Ladakh range is situated between the Indus and Sayak rivers in Kashmir. It is 350 km long, 150 km wide and about 5,300 m in height in average.

Question 34.
Name two famous valleys in Himachal Pradesh.
Answer:
Two famous valleys in Himachal Pradesh are – Kullu Valley and Kangra Valley. Question 35. Which part of the Himalayan range is known as the Eastem Himalayas?
Answer: The stretch of the Himalayan mountains lying between the Singalila range in Nepal to the Namcha Barwa peak in Arunachal Pradesh is known as the Eastern Himalayas.

Question 36.
Which part of the Himalayan range is known as the Western Himalayas?
Answer:
The stretch of the Himalayan mountains lying between the Nanga Parvat in Kashmir in the west to the river Kali in Nepal in the east, is known as the Western Himalayas.

Question 37.
What is the Tethys Himalaya ?
Answer:
The northernmost range of the Himalaya is known as the Tethys Himalaya.

Question 38.
What is the Himadri Himalaya?
Answer:
The second range of the Himalaya from north to south is known as the Himadri Himalaya. It is the highest of all the ranges and houses the series of the tallest peaks of the world. It lies between the Tethys Himalaya in the north and the Himachal Himalaya in the south.

Question 39.
Name some famous valleys lying in the Siwalik region.
Answer: Some famous valleys lying in the Siwalik region are – Dehradun, Chaukhamba, Patali etc. These narrow valleys are also known as ‘doons’.

Question 40.
Name the ranges that lie north of the Kashmir valley.
Answer:
The Himadri and the Zanskar range lies to the north of the Kashmir Valley.

Question 41.
Name some famous peaks of the Himadri range.
Answer:
Some famous peaks of the Himadri Himalaya are – Mt. Everest, Kanchenjunga, Dhabalgiri, Nanda Devi, Makalu etc.

Question 42.
Name the mountain passes that connect Sikkim and Tibet.
Answer:
The mountain passes that connect Sikkim and Tibet are Nathu-La and JelepLa. [La means pass]

Question 43.
Which pass connects Leh with Srinagar?
Answer:
Leh is connected to Srinagar by the zojila pass.

Question 44.
Which is the highest mountain pass of the world ?
Answer:
The highest mountain pass of the world is Karakoram pass. It helps to connect Kashmir with China.

Question 45.
Name some famous peaks of the Karakoram range.
Answer:
Some famous peaks of the Karakoram range are – Godwin Austin or K₂(8,611 m), Hidden Peak (8,068 m), Broad Peak (8,047 m), Gaserbrum peak (8,035 m) etc.

Question 46.
Name some famous lakes in the Kumaon Himalaya.
Answer:
Some famous lakes in the Kumaon Himalaya are – Bhimtal, Sattal, Nainital etc.

Question 47.
Where is the Kangra Valley situated ?
Answer:
The Kangra Valley is situated between the Siwalik and Dhawladhar ranges.

Question 48.
Classify the northern plain of India.
Answer:
The northern plain can be classified as – (i) Rajasthan plains or Marusthali (ii) Punjab plains (iii) Ganga plains (iv) Brahmaputra plains.

Question 49.
What do you mean by the ‘Purvachal’?
Answer:
The Himalayan range in the eastern part gets lowered and takes a hair-pin bend and spread southwand. They divide into several lower ranges that spread through Arunachal Pradesh, Assam, Nagaland, Manipur, Mizoram and Tripura. This hilly region in North-Eastern India is known as the ‘Purvachal’.

Question 50.
What is ‘Rohi’ of the Rajasthan plains?
Answer:
In the Rajasthan plains, small and narrow flood plains created by small streams flowing down the western slopes of the Aravalli range, are called ‘Rohi’.

Question 51.
What is a ‘Doab’?
Answer:
The small narrow stretch of land washed by rivers on both sides is called a ‘Doab’. It is a highly fertile long stretch of land created by silt deposition by the rivers on either side.

Question 52.
What is Bhabar?
Answer:
Bhabar is the region formed at the foothills of the Siwalik range stretching from river Indus in the west to river Teesta in the east. The region is composed of pebbles, rock fragments, coarse sand, mud particles etc. brought down by the numerous rivers.

Question 53.
Name two block mountains of India.
Answer:
i. Satpura range
ii. Vindhya range.

Question 54.
Name two residual mountains of India.
Answer:
i. Aravalli range
ii. The Eastern ghats.

Question 55.
Name two gaps present in the Western ghats.
Answer:
i. Thal ghat near Nasik
ii. Bhor ghat near Pune.

Question 56.
Why is the western coast of India more broken compared to the eastern coast?
Answer:
The western coastal plains have been formed by continuous submergence and emergence of the Western Ghats due to numerous earth movements. Hence, they are broken. But the eastern coast has been formed by deposition of silt brought down by several rivers. Thus, they are not so broken or interrupted.

Answer in brief : 3 Marks

Question 1.
Write a short note on the Karakoram range.
Answer:
The Karakoram range is bounded on the north-east by the Tibetan plateau, on the north by the Pamir plateau and on the south by rivers Indus, Gilgit and Shyok. These are very high mountains. Godwin Austin (8,611 m) is the highest peak of Karakoram. It is also known as the K₂ (King of Karakoram). It is India’s highest and the world’s second highest peak. Baltoro (60 km long), Siachen (90 km long, longest in India) etc. are some major glaciers of the Karakoram.

Question 2.
Describe the Eastern Himalaya.
Answer:
The Eastern Himalaya lie in north of West Bengal, Sikkim and Arunachal Pradesh in India, and in Bhutan. These are comparatively lower than the Western and Central Himalaya. Mt. Kanchenjunga is the highest peak of this region and the third highest peak of the world. An important mountain pass ‘Nathula’ lies between India and Tibet.

The north-eastem region of India, comparising of the states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Negaland and Tripura, also form a part of the Eastern Himalayas. Low hills like Garo, Khasi, Lushai, Patkai, Jayantia, etc. make 2 / 3 of the hilly region, intersected by valleys and plains. Important rivers like Brahmaputra and Barak flow through this region.

Question 3.
Describe the Siwalik range.
Answer:
The southernmost range of the Himalayas, stretching from west to east are known as the Siwalik. They form the foothills of the Himalayan range. The mountains are 600-1500 m high, with a width ranging from 15-50 km. They form a chain of low lying hills, that do not form a continuous chain. They enclose broad longitudinal valleys between the mountains, which are known as Doabs. The foothills of the Siwaliks are known as the Terai. The Siwalik range almost vanishes in the Eastern Himalayas due to heavy rates of erosion.

Question 4.
Describe the Plains of Rajasthan.
Answer:
The areas of the north-west, west and south-west of the Aravalli are known as the western plains of Rajasthan. The region is marked by various types of erosional features. The plain is basically stony and slopy from the foothills of the Aravallis to the north-west. Rivers Banas, Mahi and their numerous tributaries drain the region. The deeply dissected area of chappan region in the southeastern part is locally called ‘Bagar’. Southern and south-eastern Rajasthan is mostly a plateau.

Question 5.
Describe the Western Ghats.
Answer:
The Western Ghats or the Sahyadris have an average height of 1200 m and run almost parallel to the west coast for about 1600 km. The Nilgiri, Cardamom and Annamalai hills are parts of the Western Ghats. Anaimudi (2,695 m) of Annamalai is the highest peak of this region. The Dodabeta (2,637 m) is the highest peak of Niligiri hills. Important passes in the Western Ghats are Thal Ghat, Pal Ghat and Bhor Ghat. The Jog falls (250 m) is the highest waterfalls of India, located in the Sahyadri, on the river Sharavati.

Question 6.
Write a short note on the Kathiawar Peninsula.
Answer:
The Kathiawar peninsula lie in the western part of Gujarat surrounded by the Arabian sea on three sides. Traditionally it is known as Saurashtra. Its central part is an elevated.highland with hills. The Girnar and Gir hills are most prominent. Gorakhnath (1,117 m) is the highest peak of Girnar hills.

Question 7.
Write a short note on the Eastern Coastal Plains.
Answer:
The eastern coastal plains extend from the mouth of river Hugli to Kanya Kumari. It has an average width of 120 km. These are known as the Uttar Sarkars north of the delta of the Godavari river, and the Coromondal coast to the south of the delta.

Question 8.
Describe the Himachal Himalaya.
Answer:
The Himachal Himalaya lie north of the Siwalik range and south of the Himadri Himalaya. It is about 60-80 km wide and cover an area of 5,600 sq. km. The average height of the peaks is 3,500-4,500 m. The main ranges of this region are – Pir Panjal, Dhawladhar, Nagtibba, Mussurie, Mohabharat, Darjeeling etc. There are many famous valleys in this region, eg- Kashmir Valley, Kullu Valley, Kangra Valley etc. The main mountain passes present here are – Rotang, Nathula, Pir Panjal, Bidil, Banihal etc.

Question 9.
Describe the Himadri Himalaya.
Answer:
The Himadri Himalaya is the highest of the Himalayan mountain system, lying south of the Tethys Himalaya. Average height of the peaks is above 6,100 m. There are 9 peaks in this region whose height exceeds 8,000 m. The most important peaks of this region are – Mt. Everest (8848 m), Kanchenjunga (8,598 m), Makalu (8,481 m), Dhabalgiri (8,172 m), Nanga Parvat (8,126 m), Nanda Devi (7,817 m), Kamet (7,756 m), Badrinath (7,138 m), Trishul (7,120 m), Gauri Shankar (7,032 m) etc.
The region is mostly covered with permanent snow throughout the year.

Question 10.
Describe the Tethys Himalaya.
Answer:
The Tethys Himalaya is the northernmost part of the Himalayan mountain range. It mostly lie in Tibet, hence, it is also called the Tibet Himalaya. The Tethys Himalaya stretches over Jammu and Kashmir and Himachal Pradesh in India. It was created about 12-7 crore years ago due to severe earth movements. Average height of this region is 3,500 m. The main mountain ranges of this region are the Ladakh range and the Karakoram range. The famous peaks of this region are – Godwin Austin or K₂, Gaserbrum I and II, Broad Peak, Hidden Peak etc. K₂ is the highest mountain peak of India.

Question 11.
Name the important mountain passes of the Himalayas and give their locations.
Answer:

Mountain Passes	Location and connecting places
1. Jawahar or Banihal	Connects Jammu and Kashmir
2. Zoji la and Burji la	Connects Leh and Srinagar
3. Masar	Connects Leh and Tibet
4. Khardung La	Between Indus valley and Nabra valley
5. Lipu pass, Mana pass and Niti pass	Connects different parts of Uttarakhand and Tibet.
6. Rotang, Barlacha and Shipki la pass	Between Kullu and Lahut Spiti valleys
7. Nathu la, Jelep la	Connects Sikkim and Tibet
8. Ann and Tungu	Situated in Assam
9. Dom la, Thag La, Kay La, Tullang La	Connects different parts of Arunachal Pradesh with Tibet.

Question 12.
What is a ‘doon’?
Answer:
The valleys lying in the Siwalik range are called ‘doons’. The Siwalik range has been formed much later than the Himadri and Himachal Himalaya. During the formation of the Siwalik, the rivers that were flowing from the higher Himalayan ranges got interrupted and blocked, thus forming lakes and depositing pebbles, sand, silt etc. Later, the rivers eroded and made their ways through the Siwalik range as well. Thus, the waters of the lakes were removed.The depositions left back formed the ‘doons’.

Question 13.
Name some springs of the Himalayan mountains.
Answer:
(i) Hot springs : (a) Bhernag, Anantnag in Kashmir, (b) Gauri Kund in Kumaon range, (c) Tatapani in Simla etc.
(ii) Cold springs : (a) Sahastradhara in Dehradun, (b) Kempty falls in Mussoorie.

Question 14.
Name some important lakes of the Himalayan range.
Answer:
The important lakes of the Himalayan region are:

1. Dal and Wular in Kashmir
2. Nainital, Sattal, Bhimtal, Naukuchiatal etc. in Kumaon.
3. Vasuki tal, Chorabar tal near Kedarnath.
4. Roopkund, Nag kund, Devi kund near Nanda Ghunti peak.
5. Hem kund in Bhunjar valley
6. Suram kund near Nanda Devi
7. Pangon lake near China border (world’s highest salt water lake)

Question 15.
Name some important glaciers of the Himalayan range.
Answer:

1. Siachen -76 km (Spread over area)
2. Baltaro -60 km             “
3. Biyafo – 60 km              “
4. Hispar – 62 km              “
5. Gangotri -39 km           “
6. Zemu -26 km                “
7. Milam -39 km               “

Answer in details : 5 Marks

Question 1.
Describe the physiographic divisions of the Himalaya.
Answer:
The Himalaya is not a single continuous chain of mountains, but a series of parallel ranges. This can be divided into three main ranges that run parallel to each other. These are :

(a) The Greater Himalaya or the Himadri : It is the highest part of the Himalaya. The average elevation of the Himadri is 6000 m, and is permanently covered with snow. Mount Everest (8,848 m), the highest peak of the world is located here. There are some other peaks such as Kanchenjunga (8,598 m, world’s 3rd highest), Dhaulagiri ( 8,172 m), Nanga Parbat (8,126 m), Annapurna (8,076 m), Nandadevi (7,817 m) etc. Glaciers like Gangotri, yamunotri etc. originate in the Himadri.

(b) The Lesser Himalaya or the Himachal : It is a massive mountainous tract about 75 km wide and lies south of Himadri. It has an average elevation of 4,500 m. This mountain belt is highly dissected. Many of the hill stations, such as Simla, Nainital, Mussoorie, Darjeeling etc. are situated in this belt.

(c) The Outer Himalaya or Siwalik : It is the southernmost range of the Himalaya. It forms the foothills of the Himalayan range. It is 600-1500 m high with a width ranging from 15-50 km. It is a chain of low-lying hills. It is not a continuous range. There are broad longitudinal valleys in the siwalik, known as Doons. Foothills of Siwalik are known as Terai.

Question 2.
What are the importances of the Himalaya to India ?
ans.
The Himalayas have a lot of importance in India :

1. Climatic influence : The Himalaya prevents the cold winds from central Asia from entering India. It also prevents the moisture-laden monsoon winds from escaping from the land.
2. Rainfall: The Himalaya stope the monsoon winds from escaping the Indian landmass. The monsoon winds hit against the great mountain wall and cause orographic rainfall in the Indian plains.
3. Birth place of rivers : The orographic rainfall and snow-melt water give rise to numerous rivers.
4. Natural barrier : The Himalayas form a natural boundary on the north and protect the country from foreign invasions.
5. Fertile soil : The eroded materials from the mountains are deposited in the plains to make them fertile.
6. Source of irrigation, navigation and hydel power: The Himalayan rivers provide water for irrigation, navigation and hydel power generation.
7. Forest products : The Himalayan forests provide plenty of forest resources.
8. Flora and Fauna : The Himalayan forests are rich in numerous species of animals and natural vegetation.
9. Others : The Himalaya is an abode of tourists, storehouse of minerals, source of various fruits etc.

Question 3.
What is the importance of the peninsular plateau of India.
Answer:
The importance of the peninsular plateau of India are :

1. The Deccan plateau is mostly comprised black cotton soil, or regur. This region is best for the cultivation of cotton in India.
2. About 60% of the peninsular plateau is used for cultivation of jowar, bajra, wheat and rice.
3. The region is rich in mineral resources like coal, iron ore, manganese, limestone, chromite etc. which serve as raw materials for various industries.
4. Industries like cotton textile, sugar, edible oil, paper, engineering have prospered in this region.

Question 4.
Discuss the importance of the physiographic divisions of India.
Answer:
The importance or significance of the physiographic divisions of India are:

1. The variety of landforms and physical features make India a unique country.
2. The presence of mountains, plateaus, plains, deserts etc. significantly control the climate, social life and economic activities of people.
3. People on the mountains lead a tough life. Their economy mostly stands on tourism, fruit orchards, timber collection etc.
4. The people on plain lands practice agriculture, industrial activities etc.
5. Presence of mountains help in occurrence of numerous rivers that bring down a significant amount of silt.
6. The desert in the west gets heated excessively during summer, creating a low pressure cell, that attracts the monsoon winds.
7. The plateau region is a store-house of minerals with mine related occupations.

Question 5.
Discuss the importance of the Himalaya in controlling climate of India.
Answer:
The Himalaya stretches from west to east for about 2,500 km along the northern boundary of India. It has a very big influence on the climate of the country.

1. The existence of the Himalayas prevent the severely cold polar winds coming from Siberia to enter the mainland. Thus, the country is saved from the chilling colds.
2. The Himalayan mountains indirectly influence the onset of the monsoon winds.
3. The South-West monsoons cause orographic rainfall after colliding with the southern slopes of the Himalayan mountains.
4. Although located in the sub-tropical region, the altitude of the Himalayan range and its adjacent areas help to keep the climate cool and of temperate type.
5. The seasons of the country are mostly controlled by the Himalayas directly or indirectly.

Multiple Choice Questions (MCQ) : 1 Mark

Question 1.
Which of the following regions has the oldest rocks?
(A) Himalaya
(B) Aravalli
(C) Indo-Gangetic Plain
(D) Siwalik
Answer:
(B) Aravalli

Question 2.
Jojila pass is in :
(A) Kashmir
(B) Himachal Pradesh
(C) Uttar Pradesh
(D) None of these
Answer:
(A) Kashmir

Question 3.
The Himalaya in approximately – kilometre long.
(A) 2000
(B) 2500
(C) 3000
(D) 1500
Answer:
(B) 2500

Question 4.
The Himalaya is approximately broad _________ kilometer.
(A) 150 to 400
(B) 200 to 400
(C) 150 to 300
(D) 250 to 500
Answer:
(A) 150 to 400

Question 5.
The highest peak, Mount Everest is :
(A) 290.28 feet
(B) 285.28 feet
(C) 273.28 feet
(D) 269.84 feet
Answer:
(A) 290.28 feet

Question 6.
The Himalaya consists of _________ main parallel ranges from north to south
(A) two
(B) three
(C) four
(D) five
Answer:
(B) three

Question 7.
Sajhyadri ranges refer to :
(A) Siwalik
(B) Eastern Ghats
(C) Western Ghats
(D) Satpura Range
Answer:
(C) Western Ghats

Question 8.
Banihal pass is in :
(A) Punjab Himalaya
(B) Kumaun Himalaya
(C) Kashmir Himalaya
(D) Assam Himalaya
Answer:
(C) Kashmir Himalaya

Question 9.
Lahul and Spiti are located in :
(A) Kashmir Himalaya
(B) The Naga Hills
(C) The Assam Himalaya
(D) The Punjab Himalaya
Answer:
(D) The Punjab Himalaya

Question 10.
Nanda Devi lies in :
(A) Kumaun Himalaya
(B) Kashmir Himalaya
(C) Naga Hills
(D) Himachal Himalaya
Answer:
(A) Kumaun Himalaya

Question 11.
The plains of North India have the length of :
(A) 2500 km.
(B) 2300 km.
(C) 2400 km.
(D) 2250 km.
Answer:
(D) 2250 km.

Question 12.
Pir Panjal range is in :
(A) The Greater Himalaya
(B) The Middle Himalaya
(C) Siwalik
(D) Sikkim Himalaya
Answer:
(A) The Greater Himalaya

Question 13.
The average height of Siwalik is :
(A) 1500 to 2000 metre
(B) 1000 to 1500 metre
(C) 700 to 1000 metre
(D) None of these
Answer:
(A) 1500 to 2000 metre

Question 14.
Kashmir Himalaya is famous for its :
(A) Scenic beauty
(B) Dal Lake
(C) Glaciers
(D) Poverty
Answer:
(C) Glaciers

Question 15.
The Karewas of Kashmir refers to :
(A) The alluvial fans
(B) The ravines caused by gully erosion
(C) Glacial deposits
(D) Broad river terraces
Answer:
(C) Glacial deposits

Question 16.
Extensive and thick lava sheets occur in :
(A) Meghalaya
(B) Chotanagpur Plateau
(C) Western Deccan Plateau
(D) Nilgiri Hill
Answer:
(C) Western Deccan Plateau

Question 17.
Natravathi rises in the mountain range of :
(A) Western Ghat
(B) Satpura Range
(C) Eastern Ghat
(D) Aravalli Range
Answer:
(A) Western Ghat

Question 18.
Western Coastal plains of India are :
(A) Flat
(B) Round
(C) Level
(D) None of these
Answer:
(A) Flat

Question 19.
How much percentage land area of India is covered by mountains?
(A) 10.7
(B) 12.7
(C) 9.7
(D) 11.7
Answer:
(A) 10.7

Question 20.
The area of Ganga plain is :
(A) 3,57,000 sq. km.
(B) 3,20,000 sq.km.
(C) 3,50,000 sq.km.
(D) 3,40,000 sq.km.
Answer:
(A) 3,57,000 sq. km.

Question 21.
The Great plain has been subjected to …. throughout its period of existence.
(A) the denudation processes
(B) the degradational processes
(C) the aggradational processes
(D) the weathering processes
Answer:
(C) the aggradational processes

Question 22.
The Garo, Khasi and Jaintia hills were formed in the same age as the :
(A) Himalaya
(B) Siwalik range
(C) Malwa plateau
(D) Himachal range
Answer:
(C) Malwa plateau

Question 23.
The vigorous glacial action of the Himalayan rivers in the past is proved by :
(A) the awe-inspiring gorges
(B) the sedimentary beds of the Kashmir valley
(C) the hanging valleys at lower altitudes
(D) the frequent shifts in the courses of the rivers
Answer:
(C) the hanging valleys at lower altitudes

Question 24.
Palghat is a mountain pass of :
(A) Eastern Ghat
(B) Satpura
(C) Western Ghat
(D) Maikal Range
Answer:
(C) Western Ghat

Question 25.
The name of the desert of Rajasthan is :
(A) Bagar
(B) Rohi
(C) Hamada
(D) Marusthali
Answer:
(D) Marusthali

Question 26.
What is the most important geographic use of the Himalayas to India?
(A) Prevention of invasions
(B) Valuable source of timber
(C) They prevent the monsoons from crossing to the north and also serve as a reservoir of water from which our perennial rivers flow
(D) They protect India from the icy cold north winds
Answer:
(C) They prevent the monsoons from crossing to the north and also serve as a reservoir of water from which our perennial rivers flow

Question 27.
Which of the following mountains are the oldest according to geological history?
(A) Nilgiri
(B) Satpura Range
(C) Vindhya
(D) Aravalli
Answer:
(D) Aravalli

Question 28.
Where mainly in India would you find denuded rocks ?
(A) Himalayan region
(B) Peninsular Plateau
(C) Valleys
(D) Everywhere
Answer:
(B) Peninsular Plateau

Question 29.
The average height of the Himalaya is :
(A) 5850 metre
(B) 9050 metre
(C) 4800 metre
(D) 5000 metre
Answer:
(A) 5850 metre

Question 30.
India’s coastline is long to the extent of :
(A) 1400 mile
(B) 1000 mile
(C) 3500 mile
(D) 5100 mile
Answer:
(C) 3500 mile

Question 31.
The west coast of India is :
(A) Levelled
(B) Low lying
(C) Very well indented
(D) None of these
Answer:
(C) Very well indented

Question 32.
The Lakshadwees islands are located in :
(A) Bay of Bengal
(B) Arabian Sea
(C) Indian Ocean
(D) Persian Gulf
Answer:
(B) Arabian Sea

Question 33.
Purvanchal refers to the :
(A) Mountain ranges on the eastern borders or India
(B) Eastern Ghats
(C) Chotanagpur Plateau
(D) Assam Himalayas
Answer:
(A) Mountain ranges on the eastern borders or India

Question 34.
The Himalayan ranges consist of
(A) A single range with peaks exceeding 8000 metres
(B) Three parallel ranges with intervening longitudinal valleys
(C) Two parallel ranges with a plateau in between
(D) Four parallel ranges
Answer:
(B) Three parallel ranges with intervening longitudinal valleys

Question 35.
Highest peak of Deccan plateau of Southern India is :
(A) Dodabeta
(B) Patkoi
(C) Anaimudi
(D) Gurushikhar
Answer:
(C) Anaimudi

Question 36.
Name the coast where the lagoons are locally known as Kayal :
(A) Malabar
(B) Konkan
(C) Coromandel
(D) Karnataka
Answer:
(A) Malabar

Question 37.
Highest peak of Aravalli Hills :
(A) Dodabeta
(B) Gurushikhar
(C) Dhupgarh
(D) Amar Kantak
Answer:
(B) Gurushikhar

Question 38.
Highest peak of Satpura hills :
(A) Dhupgarh
(B) Anaimudi
(C) Sadal Peak
(D) Nanga Pahar
Answer:
(A) Dhupgarh

Question 39.
The main difference between the Eastern Ghats and the Western Ghats is in the matter of :
(A) continuity
(B) proximity to coast
(C) ending in Nilgiri
(D)height
Answer:
(A) continuity

Question 40.
The region on the southern side of the Siwalik is called the :
(A) Dunes
(B) Bhabhar
(C) Terai
(D) Khadar
Answer:
(B) Bhabhar

Question 41.
The Nilgiri is part of the :
(A) Eastern Ghats
(B) Western Ghats
(C) Vindhyachal
(D) Tamil Nadu Hills
Answer:
(B) Western Ghats

Question 42.
Which of the following is characterised by excessive dampness with a thick growth forest and a variety of wildlife ?
(A) Bhabhar
(B) Bhangar
(C) Terai
(D) Khadar
Answer:
(C) Terai

Question 43.
Match the following

Answer:

Question 44.
Lakshadweep island is of :
(A) Coral origin
(B) Volcanic origin
(C) Tectonic origin
(D) Alluvial origin
Answer:
(A) Coral origin

Question 45.
India has total land frontier of :
(A) 10000 mile
(B) 12000 mile
(C) 9425 mile
(D) 7000 mile
Answer:
(C) 9425 mile

Question 46.
The average elevation of Vindhya mountain is :
(A) 500 metre
(B) 200 metre
(C) 400 metre
(D) 300 metre
Answer:
(D) 300 metre

Question 47.
The Ganga-Indus Plain widens :
(A) from east to west
(B) from west to east
(C) at the middle
(D) nowhere
Answer:
(A) from east to west

Question 48.
The Peninsular Plateau of India extends up to :
(A) Mizo hills
(B) Himachal Himalayas
(C) Assam valley
(D) Meghalaya hills
Answer:
(D) Meghalaya hills

Question 49.
What is the most important characteristic of the islands (Indian) located in the Arabian Sea?
(A) They are all very small in size
(B) They are all of coral origin
(C) They have a very dry climate
(D) They are extended parts of the mainland
Answer:
(B) They are all of coral origin

Question 50.
What do the basalt layers of the Dcccan indicate?
(A) The influence of weathering
(B) The immense erosional activity of the rivers
(C) Huge volcanic eruptions in the distant past
(D) All the above
Answer:
(C) Huge volcanic eruptions in the distant past

Question 51.
Highest peak of Anaimalai range :
(A) Anaimudi
(B) Amarkantak
(C) Kalsubai
(D) Mahendragiri
Answer:
(A) Anaimudi

Question 52.
The coast of Tamil Nadu is known as :
(A) Malabar
(B) Konkan
(C) Andhra coast
(D) Coromandel
Answer:
(D) Coromandel

Question 53.
The coast of Kerala is known as :
(A) Uttar Sarkar
(B) Coromondel
(C) Malabar
(D) Konkan coast
Answer:
(C) Malabar

Question 54.
Highest plateau of India is :
(A) Deccan Plateau
(B) Ladakh
(C) Meghalaya
(D) Malab Plateau
Answer:
(B) Ladakh

Question 55.
Which of the following ranges separates the Kashmir valley from the Indus valley?
(A) Siwalik range
(B) Pir Panjal range
(C) Dhauladhar range
(D) Great Himalayan range
Answer:
(D) Great Himalayan range

Question 56.
Which of the following ranges act as a natural barries between India and Tibet?
(A) Jelep La
(B) Kalimpong
(C) Lipu Lekh
(D) Himalayas
Answer:
(D) Himalayas

Question 57.
______ is known as the Queen of the Himalayas.
(A) Dhawlagiri
(B) Kanchanjunga
(C) Nandadevi
(D) K₂
Answer:
(B) Kanchanjunga

Question 58.
The Garo, Khasi and Jayantia hills were formed in the same age as the :
(A) Himalayas
(B) Siwaliks
(C) Malwa Plateau
(D) Himachal
Answer:
(C) Malwa Plateau

Question 59.
________ is considered as the remnant of the Gondwanaland.
(A) The gangetic plain
(B) The Himalayas
(C) The Deccan plateau
(D) The Punjab Plains
Answer:
(C) The Deccan plateau

Question 60.
The largest plateau of india is :
(A) Betwa plateau
(B) Deccan plateau
(C) Malwa plateau
(D) Chotanagpur plateau
Answer:
(B) Deccan plateau

Question 61.
Mt. Abu, a small hilly block is separated from the Aravalli range by :
(A) Malwa plateau
(B) Guru-Sikhar valley
(C) Narmada valley
(D) Banas valley
Answer:
(D) Banas valley

Question 62.
Bhabar and Terai belts are wellformed in :
(A) Uttar Pradesh
(B) Bihar
(C) West Bengal
(D) Assam
Answer:
(A) Uttar Pradesh

Fill in the blanks : 1 Mark

1. Himalayas owe its origin in the _______ Epoch.
2. According to geological history, the oldest mountain is Aravalli, and the youngest is _______.
3. _______ is the highest peak of the Naga Range.
4. The length of the Himalayas between Indus gorge and Brahmaputra gorge is _______ km.
5. Nokrek is the highest peak of the _______ hills.
6. The Malwa plateau is a _______ plateau.
7. The North-Indian plains extend for _______ km between the mouth of the Ganga and the Indus.
8. The total length of India’s coastline is about _______ km.
9. The _______ range forms the water divide between Narmada and Tapti rivers.
10. The Himalayas run in the East-West direction along the entire northern boundary of India for _______ km.
11. The lesser or middle Himalayas have an average elevation of about _______ m.
12. Aravalli hills are located in the _______ of the Malwa plateau.
Answer:
1. Oligocene
2. Himalayas
3. Saramati
4. 2400 km
5. Garo
6. Piedmont
7. 3200
8. 7500
9. Satpura
10. 2400
11. 3500-5000 m
12. North-West

State True or False : 1 Mark

1. Malabar coast is a part of Eastern coast of India. [ ]
2. Dehradun valley, Udhampur valley, chaukhamba valley, etc. are located in the Siwaliks. [ ]
3. Nagtibba is the most important range of the lesser Himalayas. [ ]
4. The Siachen glacier is located in Nubra valley. [ ]
5. Zanskar and PIr Panjal ranges are located in Himachal Pradesh [ ]
6. Aravalli range is an example of block mountains. [ ]
7. Andhra Pradesh has the largest coast line in India [ ]
Answer:
1. True
2. True
3. False
4. True
5. False
6. False
7. True

Match the following : 1 Mark

List I	List II
A. Zojila pass	i. Sikkim
B. Bara Lacha La pass	ii. Uttar Pradesh
C. Niti pass	iii. Himachal Pradesh
D. Jelep la pass	iv. Kashmir

Answer:

List I	List II
A. Zojila pass	iv. Kashmir
B. Bara Lacha La pass	iii. Himachal Pradesh
C. Niti pass	i. Sikkim
D. Jelep la pass	ii. Uttar Pradesh

Answer in few words : 1 Mark

Question 1.
Which is the highest peak of India ?
Answer:
Godwin Austin or K₂(8,611 m)

Question 2.
Where is the highest peak of India located ?
Answer:
In the Karakoram range.

Question 3.
Where does the largest glacier of India lie?
Answer:
Largest glacier of India, Siachen (90 m) lies in the Karakoram range.

Question 4.
What is the other name of the greater Himalaya ?
Answer:
The Himadri.

Question 5.
What is the other name of the outer Himalayas?
Answer:
The Siwalik.

Question 6.
Name the regional divisions of the Himalayas.
Answer:

• Western Himalaya
• Central Himalaya
• Eastern Himalaya.

Question 7.
Which rivers drain the plains of Rajasthan ?
Answer:
River Banas, Mahi and their numerous tributaries.

Question 8.
Name the highest peak of the Satpura range.
Answer:
Dhupgarh (1,350 m)

Question 9.
Name the another identity of the Western Ghats.
Answer:
Sahyadris.

Question 10.
Which is the highest peak of the Deccan plateau ?
Answer:
Anaimudi (2,695m) of Annamalai hills.

Question 11.
Which is the highest peak of the Nilgiri hills ?
Answer:
Dodabeta (2,637 m)

Question 12.
Name the highest waterfalls of India.
Answer:
The Jog Falls (250 m) on the river Sharavathi.

Question 13.
Which is the highest peak of the Eastern Ghats ?
Answer:
Mahendragiri (1,501 m)

Question 14.
Name the oldest mountain range of India.
Answer:
Aravalli range.

Question 15.
Which state of India is known as the ‘Land of five mountains’?
Answer:
Tripura.

Question 16.
Name the highest peak of the Aravalli range.
Answer:
Gurushikhar.

Question 17.
Name the lava plateau of India.
Answer:
The Deccan plateau, the Malwa plateau.

Question 18.
Name a dead volcano present in India.
Answer:
Narkondam of the Andaman and Nicobar islands.

Question 19.
Which is the easternmost mountain range of India ?
Answer:
Namchabarwa.

Question 20.
Which pass connects Kashmir Valley to Leh ?
Answer:
The Zojila Pass.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 5.1 Location and Administrative Divisions of India offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 5.1 Question Answer – Location and Administrative Divisions of India

Answer in brief : 2 Marks

Question 1.
State the boundaries of India.
Answer:
The boundaries of India are:

1. North → China, Nepal and Bhutan.
2. North-West → Pakistan and Afghanistan.
3. West → Pakistan and Bay of Bengal.
4. South → Sri Lanka and Indian Ocean.
5. East → Bangladesh, Myanmar and Bay of Bengal.

Question 2.
Why is India called a Peninsula ?
Answer:
India is bounded by three water bodies on three sides (Arabian sea in the West Indian Ocean in the South, Bay of Bengal in the East) and attached to land only on the north. Thus it is called a Peninsula.

Question 3.
What is the name of the boundary between India and China and India and Pakistan?
Answer:
Boundary between India and China Macmohan Line. Boundary between India and Pakistan Radcliffe line.

Question 4.
What is the LOC?
Answer:
LOC or Line of Control is the boundary between the part of Kashmir under India and the part that belongs to Pakistan.

Question 5.
Mention the latitudinal and longitudinal extent of India.
Answer:
The main landmass of India lies between the latitudes 8° 04′ 24″ N to 37° 06′ N, and longitudes 68° 07′ 53″ E to 97° 24′ 47″ E.

Question 6.
What were the criteria considered for the basis of division of states after independence?
Answer:
The basis of division of states of India after independence are – Language, Administrative advantage and skill, Culture, Physical and Geographical similarities, and Economic stability.

Question 7.
What is the position of India in Asia and the World with respect to area?
Answer:
India ranks 7^th in the world (after Russia, Canada, China, USA, Brazil and Australia) and 2^nd in Asia (after China) with respect to area.

Question 8.
What is the length of the coastline of India ?
Answer:
The length of the coastline of India including the mainland as well as the Lakshadweep and Andaman and Nicobar Islands is 7,517 km.

Question 9.
What is Indira Point ?
Answer:
Indira Point is the southernmost point of India. It is the southernmost point of the great Nicobar Island. Previously it was known as the Pymalian point.

Question 10.
Name 4 states of India lying in the north east.
Answer:
Assam, Meghalaya, Manipur, Nagaland.

Question 11.
Name 4 Union Territories of India.
Answer:
Delhi, Pondicherry, Chandigarh, Andaman and Nicobar islands.

Question 12.
Name 4 states along the coast of the Bay of Bengal.
Answer:
Tamil Nadu, Andhra Pradesh (now Seemandhra), Odisha, West Bengal.

Question 13.
Name 4 states along the coast of the Arabian Sea.
Answer:
Kerala, Karnataka, Goa, Maharashtra and Gujarat.

Question 14.
Which islands are separated by the 10° Channel ?
Answer:
The 10° Channel separates the Andaman islands and Nicobar islands.

Question 15.
Which islands are separated by the 9° Channel ?
Answer:
Lakshadweep islands and Minicoy islands.

Question 16.
Which islands are separated by the 8° Channel ?
Answer:
Minicoy islands and Maidives islands.

Question 17.
What is the Durand line?
Answer:
Durand line is the boundary between India and Afghanistan. It was named in 1896.

Question 18.
How has India been designated in the constitution since 26th January 1950 ?
Answer:
Since 26 January 1950, India has been designated as a Sovereign, Socialist, Secular, Democratic, Republic country in the Constitution.

Question 19.
What is the East-West and North-South extent of India ?
Answer:
i. East-West extent of India is 2,933 km.
ii. North-South extent of India is 3,214 km.

Question 20.
How many states and Union Territories are presently there in India ?
Answer:
Presently there are 29 states and 7 Union Territories in India.

Question 21.
Name the smallest and largest states of India.
Answer:
The smallest state of India is Goa and the largest state is Rajasthan.

Question 22.
Name the smallest and largest Union Territories of India.
Answer:
The smallest Union Territory of India is Lakshadweep and the largest one is Andaman and Nicobar islands.

Question 23.
Which is the southernmost point of the mainland of India ?
Answer:
The southernmost point of the mainland of India is Kanyakumari in Tamil Nadu.

Question 24.
Name the smallest and largest neighbouring countries of India.
Answer:
The smallest neighbouring country of India is Maldives and the largest neighbouring country is China.

Question 25.
Name 2 neighbouring countries of India on the western border.
Answer:
Two neighbouring countries of India on the western border are Pakistan and Afghanistan.

Question 26.
Name 2 northernmost states of India and their capitals.
Answer:
i. Jammu \ Kashmir – Srinagar.
ii. Himachal Pradesh – Shimla.

Question 27.
Name 2 westernmost states of India and their capitals.
Answer:
i. Gujarat – Gandhinagar.
ii. Rajasthan – Jaipur.

Question 28.
Name 2 southernmost states of India and their capitals.
Answer:
i. Tamil Nadu – Chennai.
ii. Kerala – Thiruvananthapuram.

Question 29.
Name 2 easternmost states of India and their capitals.
Answer:
i. Arunachal Pradesh – Itanagar.
ii. Nagaland – Kohima.

Question 30.
Where is the Price channel located ?
Answer:
The Price channel lies between the Mini Nicobar and Great Nicobar Islands.

Answer in brief : 3 Marks

Question 1.
Mention the location and latitudinal extent and longitudinal extent of India.
Answer:
India is located in southern Asia between the latitudes -8° 04′ 24” N to 37° 06′ N and longitudes -68° 07′ 53” E to 97° 24′ 47” E. Total area is about 32 lakh 87 thousand 263 sq. km. It is bounded by the Himalayas, China, Nepal and Bhutan on the north. The North-West is bounded by Pakistan and Afghanistan. The West is bounded by Pakistan and the Arabian sea. The east is bounded by Myanmar, Bangladesh and the Bay of Bengal. The south is bounded by the Indian Ocean and Srilanka.

Question 2.
How does the peninsular location of India influence the land and life of the people?
Answer:

The advantages of the peninsular location of India are :

1. India can conduct international trade through waterways very easily due to presence of oceans and seas on three sides.
2. Nearness to sea helps in development of navigation and fishing activities.
3. Presence of the vast water bodies influences the weather and climate of the country.
4. Presence of vast water bodies give natural protection from invasions and attacks by enemies.
5. Water bodies help to maintain cordial relations with the neighbouring countries as well.

Question 3.
Discuss in brief the history of reorganisation of states of India after independence.
Answer:
The borders of the states inherited from British India were not suitable for easy administration. Hence, after independence, the need for reorganisation of states of India was felt. Several controversies arose, regarding what should be the basis of reorganisation of states. Hence, the government of India constituted the State Reorganisation commission (SRC) to undertake and resolve the issue, which passed the State Reorganisation Act in 1956. By the Act, the states were reorganised on the basis of – language, administrative skill and advantage, Culture, physical and cultural similarities and economic stability.

Question 4.
Name the various neighbouring countries of India.
Answer:
The neighbouring countries of India are:

1. Northern neighbours : China (largest neighbouring country), Nepal, Bhutan (Smallest neighbouring country touching the mainland).
2. North-Western neighbours : Afghanistan.
3. Western neighbours : Pakistan (second largest neighbouring country)
4. Southern neighbours : Sri Lanka (separated from the mainland of India by the Gulf of Mannar and Palk Strait)
5. South-Western neighbours : Maldives (smallest neighbouring country away from the mainland, south of the Lakhadweep.)
6. Eastern neighbours : Myanmar (third largest neighbouring country), Bangladesh (fourth largest neighbouring country).

Question 5.
Name the States of India that were newly formed in \mathbf{2 0 0 0 .
Answer:
The states that were formed in 2000 after breaking from the former states are:

Question 6.
Name the Union Territories of India.
Answer:
The Union Territories of India are :

1. i. Andaman and Nicobar Islands (largest)
2. Daman and Diu
3. Chandigarh
4. Dadra and Nagar Haveli
5. Pondicherry
6. Lakshadweep
7. Delhi (National Capital Region)

Question 7.
What is an ‘enclave’?
Answer:
Small areas or settlements of one particular country lying within the territories of the neighbouring countries, is called ‘enclaves’. Eg – There are 162 enclaves of Bangladesh present in Indian territory and 111 enclaves of India present within the territories of Bangladesh.
According to a historic treaty signed on 31 July 2015, between India and Bangladesh, the 162 Bangladeshi enclaves lying within India have been handed over to Bangladesh government and the families residing in those enclaves (222 families) have settled in the Indian territory. 51 enclaves of India have been converted to Indian territory so far.

Answer in details : 5 Marks

Question 1.
Discuss the various basis of division of states of India after independence.
Answer:
The basis of division of states of India after independence are :
i. Language : India is a land where people speak different languages in different parts of the country. Based on this, the states were demarcated in 1956, designating the region speaking a common language as one state. Eg-the region where people mostly speak Assamese was demarcated as Assam.

ii. Administrative advantage and skill : Although language was a criterion of demarcating states, only this could not work very well. Eg-Hindi is spoken in Uttar pradesh, Bihar, Jharkhand, Madhya Pradesh and Uttaranchal. But if all these states were kept united as one single state, it would have covered a huge area, causing difficulty in administration. Also, Bengali is spoken in West Bengal and Tripura. But due to physical distance, these two states could not be put together.

iii. Culture : Even though language spoken is the same, the local cultures and rituals followed in a particular region may vary. Hence, for administrative efficiency, these regions are fragmented into different states. Eg-Bihar has been fragmented into Bihar and Jharkhand.

iv. Physical and geographical similarities : Physical and geographical conditions influence the culture and life style of people. It also plays an important role in administrative works.

v. Economic stability : Uniform economic condition helps in planning and execution of administrative and developmental works. Hence, economic condition of the region is also judged before demarcating a state.

Question 2.
State the division of states that occured in India from 1947 to 1950 , after independence.
Answer:
India achieved its freedom on 15 August 1947. On 14 and 15 August, the mainland was divided into two countries – India and Pakistan. The part of independent India was divided into 9 governor ruled states, 4 chief commissioner ruled states and more than 600 independent small national states. In 1948-49, by the efforts of Sardar Ballav Bhai Patel, the smaller national states were included within the mainland of India. In 1949, when the Constitution of India was framed and accepted on 26 January, there were 28 states and one National Territory in India.

Question 3.
Discuss the importance of the geographical location of India.
Answer:

The importance of the geographical location of India are as follows :
i. Central location : The portion of India from 10° N-23[altex]\frac{1}{2}[/latex]° N latitudes lie in the tropical region and the portion from 23 [altex]\frac{1}{2}[/latex]° N 30° N latitudes lie in the sub-tropical region.

ii. Central location within Asia : India lies in the centre of the South Asian countries. Thus, it plays an important role in trade and commerce between the SouthEastern and South-Western countries of Asia.

iii. Effects on the Indian Ocean : India being located just at the north of the Indian Ocean, influences the currents of the Indian Ocean to a large extent.

iv. Trade through waterways : India being surrounded by seas and oceans on three sides (Arabian Sea in the west, Indian Ocean in the south, Bay of Bengal in the east) enjoys a great advantage in trade by waterways with other countries.

Natural boundary : India enjoys natural boundaries on almost all sides – the Himalaya in the north, Arabian Sea and the Thar desert in the west, Indian Ocean in the south, Bay of Bengal in the east. This has provided natural security to the land and has helped to reduce expenses on millitary and security purposes.

vi. Relation with neighbouring countries : India is a very important member of the foundation called SAARC (South Asian Association of Regional Co-operation). It helps to promote and protect the interests of the neighbouring countries of Pakistan, Nepal, Bhutan, Bangladesh, Sri Lanka and Maldives.

Question 4.
Why are the countries of India and its neighbours together called ‘Indian subcontinent?
Answer:
India along with its neighbours Pakistan, Nepal, Bhutan, Bangladesh and Sri Lanka are known as the ‘Indian subcontinent’. This is because of the following factors :
i. Large size : The size of these countries adjoining each other together is as large as a continent. India along with its neighbours cover an area of about 52,00,000 sq. km.

ii. Similarities in physiography : Usually the continents are surrounded by water entirely or on three sides. India along with its neighbours is surrounded by water on three sides, which is similar to that of continents. Also, like continents, Indian subcontinent contains all kinds to topographic regions like mountains, plateaus, plains, deserts, valleys etc.

iii. Similarities in climate : Like a continent, the Indian subcontinent has a number of climates in the different parts of the huge landmass. There are regions of heavy snowfall to regions of tremendous heat. The driest and wettest places of Asia also lie within this region. The variations in climate in different topographical regions make it similar to that of a continent.

iv. International rivers : Continents often have rivers that flow within two or more countries. In the Indian subcontinent, the Indus flows through India and Pakistan, the Brahmaputra originates in Tibet, flows through India and Bangladesh, and the Ganga also flows through India and Bangladesh.

v. Culture : Like a continent, the Indian subcontinent exhibits a large variety in caste, creed, colour, language, food habits, housing, religion, economic activities, etc. of people. Ancient civilisation of Mohenjo Daro and Harappa also belong to this region.

Thus, it is rightly said that the region is a subcontinent, and a mini representation of the entire world.

Multiple Choice Questions (MCQ) : 1 Mark

Question 1.
India lies :
(A) mainly in the northern hemisphere
(B) entirely in the northern hemisphere
(C) on the equator
(D) more in the southern hemisphere
Answer:
(B) entirely in the northern hemisphere

Question 2.
The Arabian Sea lies to :
(A) north-east of India
(B) south-east of India
(C) south-west of India
(D) north-west of India
Answer:
(D) north-west of India

Question 3.
Palk Strait separates India from :
(A) Pakistan
(B) China
(C) Andaman Island
(D) Sri Lanka
Answer:
(D) Sri Lanka

Question 4.
Lakshadweep Islands are situated in :
(A) Arabian Sea
(B) Palk Strait
(C) Indian Ocean
(D) Bay of Bengal
Answer:
(A) Arabian Sea

Question 5.
India’s latitudinal and longitudinal extent, measured in degrees, are almost the same, but its east-west extent, measured in in km, is greater than its north-south extent. This is due to the fact that :
(A) longitudes are not parallel lines
(B) the distance between latitudes remains the same but the distance between longitudes is greatest at the equator and nil at the poles where all longitudes join
(C) all longitudes, with their opposites, form great circles
(D) the earth is not a perfect sphere
Answer:
(B) the distance between latitudes remains the same but the distance between longitudes is greatest at the equator and nil at the poles where all longitudes join

Question 6.
The longest shore-line is along the state of :
(A) Gujarat
(B) Maharashtra
(C) Odisha
(D) Kerala
Answer:
(A) Gujarat

Question 7.
Which of the following States of India do not lie entirely in the Tropical Zone of the earth?
(A) Kerala and Tamil Nadu
(B) Gujarat
(C) Karnataka
(D) Maharashtra and Andhra Pradesh
Answer:
(B) Gujarat

Question 8.
The Indian States which have common borders with Pakistan are :
(A) Gujarat, Himachal Pradesh, Haryana and Jammu and Kashmir
(B) Gujarat, Jammu and Kashmir, Punjab and Rajasthan
(C) Jammu and Kashmir, Haryana, Rajasthan and Punjab
(D) Jammu and Kashmir, Himachal Pradesh, Punjab and Rajasthan
Answer:
(B) Gujarat, Jammu and Kashmir, Punjab and Rajasthan

Question 9.
Which of the following Indian islands lies between India and Sri Lanka?
(A) Elephanta
(B) Nicobar
(C) Rameshwaram
(D) Salsette
Answer:
(C) Rameshwaram

Question 10.
The sun rises in Arunachal Pradesh two hours before it does in Dwaraka in Gujarat. This is because the former is :
(A) higher in elevation than Dwaraka
(B) situated further north than Dwaraka
(C) situated further east (about 30° longitude) than Dwaraka
(D) situated about 30° east of Dwaraka and the earth rotates from west to east
Answer:
(D) situated about 30° east of Dwaraka and the earth rotates from west to east

Question 11.
Which of the Indian States has the maximum number of common borders with other Indian States ?
(A) West Bengal
(B) Madhya Pradesh
(C) Uttar Pradesh
(D) Karnataka
Answer:
(B) Madhya Pradesh

Question 12.
Which one of the following gives the three largest states of India (in terms of geographical area) in the correct descending order?
(A) Madhya Pradesh, Rajasthan, Maharashtra
(B) Uttar Pradesh, Madhya Pradesh, Andhra Pradesh
(C) Madhya Pradesh, Maharashtra, Andhra Pradesh
(D) Madhya Pradesh, Uttar Pradesh, Rajasthan
Answer:
(A) Madhya Pradesh, Rajasthan, Maharashtra

Question 13.
Which one of the states not bisected by the Tropic of Cancer is ?
(A) Odisha
(B) Gujarat
(C) West Bengal
(D) Rajasthan
Answer:
(A) Odisha

Question 14.
Of the following towns which one does not lie in the north of the Tropic of Cancer ?
(A) Allahabad
(B) Patna
(C) Bhopal
(D) Jhansi
Answer:
(A) Allahabad

Question 15.
The southern-most point of Indian territory is in :
(A) Tamil Nadu
(B) Lakshadweep
(C) Trivandrum
(D) Andaman and Nicobar Islands
Answer:
(D) Andaman and Nicobar Islands

Question 16.
At present the number of Union territories in India is :
(A) 6
(B) 7
(C) 8
(D) 9
Answer:
(A) 6

Question 17.
The latitude of Indira point is :
(A) 6° 04’N
(B) 6° 40’N
(C) 6° 45’N
(D) 6° 50’N
Answer:
(C) 6° 45’N

Question 18.
The Redcliffe Line demarcates the boundary between
(A) India and China
(B) India and Pakistan
(C) Pakistan and Afghanistan
(D) India and Afghanistan
Answer:
(B) India and Pakistan

Question 19.
The main basis of the delineation of states and union territories of India was
(A) culture
(B) language
(C) administrative efficiency
(D) dress
Answer:
(B) language

Question 20.
Lakshadweep is located near
(A) Konkan
(B) Coromandel
(C) Malabar
(D) Andhra coast
Answer:
(C) Malabar

Question 21.
The southernmost point of Indian landmass is
(A) Cape Comorin
(B) Kannyakumari
(C) Indira point
(D) Indira kol
Answer:
(C) Indira point

Question 22.
The distance between the northern most point in Kashmir and Kanyakumari covers about-
(A) 20° latitude
(B) 25° latitude
(C) 30° latitude
(D) 35° latitude
Answer:
(C) 30° latitude

Question 23.
India, our motherland, liés to the north of equator between 8°4′ to north latitude –
(A) 51° 2′
(B) 43° 5′
(C) 37° 67′ 53”
(D) 31° 2′
Answer:
(C) 37° 67′ 53”

Question 24.
The territorial waters of India extends upto
(A) 5 nautical miles
(B) 12 nautical miles
(C) 15 nautical miles
(D) 2 nautical miles
Answer:
(B) 12 nautical miles

Question 25.
According to area, the largest state of India is
(A) Madhya Pradesh
(B) Rajasthan
(C) Maharashtra
(D) Uttar Pradesh
Answer:
(B) Rajasthan

Question 26.
The boundary line between India and China is called
(A) Radcliff line
(B) Durand line
(C) Mc Mohan line
(D) Red line
Answer:
(C) Mc Mohan line

Question 27.
The capital of Lakshadweep is
(A) Port Blair
(B) Silvassa
(C) Aigawl
(D) Kavaratti
Answer:
(D) Kavaratti

Question 28.
A state which has two capitals is
(A) Uttar Pradesh
(B) Maharashtra
(C) Punjab
(D) Haryana
Answer:
(D) Haryana

Question 29.
Which of the following Indian State does not lie on Indo-Bangladesh border?
(A) Assam
(B) Mizoram
(C) Manipur
(D) Tripura
Answer:
(C) Manipur

Question 30.
Which of the following is not a Union Territory ?
(A) Pondicherry
(B) Lakshadweep
(C) Arunachal Pradesh
(D) Andaman and Nicobar islands
Answer:
(C) Arunachal Pradesh

Question 31.
Port Blair is situated in
(A) North Andaman
(B) South Andaman
(C) Middle Andaman
(D) Little Andaman
Answer:
(B) South Andaman

Question 32.
Lakshadweep is a group of islands.
(A) 22
(B) 27
(C) 32
(D) 35
Answer:
(B) 27

Question 33.
Which of the following Indian state does not lie on the Indo-Nepal border?
(A) Bihar
(B) Uttaranchal
(C) Sikkim
(D) Himachal Pradesh
Answer:
(D) Himachal Pradesh

Question 34.
Duncan pass lies between
(A) India and Sri Lanka
(B) India and Nepal
(C) North and East Andaman
(D) Andaman and Nicobar
Answer:
(C) North and East Andaman

Question 35.
What separates Daman and Diu ?
(A) Narmada river
(B) Gulf of Khambat
(C) Gir hills
(D) Tapi river
Answer:
(B) Gulf of Khambat

Question 36.
Which of the following Indian state is land locked ?
(A) Andhra Pradesh
(B) Bihar
(C) West Bengal
(D) Kerala
Answer:
(B) Bihar

Question 37.
Where does Aksai Chin lie?
(A) Near Leh
(B) North-east corner of Jammu and Kashmir
(C) Along the Zanskan Mountains
(D) South of Siachen Glacier
Answer:
(B) North-east corner of Jammu and Kashmir

Question 38.
Which of the following countries have the longest international boundary with India?
(A) Bangladesh
(B) Bhutan
(C) China
(D) Pakistan
Answer:
(A) Bangladesh

Question 39.
Which important latitude passes through India ?
(A) Equator
(B) Arctic circle
(C) Tropic of Capricorn
(D) Tropic of Cancer
Answer:
(D) Tropic of Cancer

Question 40.
India lies in the
(A) Northern hemisphere
(B) North-eastern hemisphere
(C) Southerrn hemisphere
(D) South-eastern hemisphere
Answer:
(B) North-eastern hemisphere

Fill in the blanks : 1 Mark

1. The smallest state of India is ________.
2. _______ is the most populous state of India.
3. ________ is the least populous state of India.
4. Number of languages accepted by the constitution of India is________.
5. The central meridian of India is________.
6. The basis of state reformation in 1956 was________.
7. Andhra Pradesh has been parted to form the state of________.
8. SAARC consists of _______ members.
9. The headquarter of SAARC is located at________.
10. _______ is the largest state of India.
11. ________ is the most densely populated state of India.
12. The state reforming commission was established in India in________.
13. India extends for _______ km from east to west.
14. The length of the Indian boundary is ________ km.
15. The word ‘India’ has been derived from the greek word________.
Answer:
1. Goa
2. Uttar Pradesh
3. Sikkim
4. 22
5. 82 \(\frac{1{2\)° E
6. Language
7. Telengana
8. 6
9. Kathmandu
10. Rajasthan
11. Bihar
12. 1953
13. 2933
14. 15,200
15. Indoi

State True or False : 1 Mark

1. The largest district of India is Kachch in Gujrat. [ ]
2. The enclaves of Bangladesh have been joined with the state of Assam. [ ]
3. The north-south extent of India is 3214 km. [ ]
4. Chennal is known as the gateway of India. [ ]
5. The least number of districts is present in the state of Sikkim. [ ]
6. The largest Union Territory of India is the Andaman and Nicobar Islands. [ ]
7. The smallest Union Territory of India is Lakshadweep. [ ]
8. A peninsula is surrounded by water on four sides. [ ]
9. The capital of Jharkhand is Patna. [ ]
10. The capital of the newly formed state of Telengana is Hyderabad. [ ]
11. Nagaland has been declared as a state in 1963 . [ ]
12. Punjab was divided to form the states of Punjab and Haryana. [ ]
13. Kerala was previously known as Mahisoor. [ ]
14. Pondicherry is the smallest Union Territory of India. [ ]
15. Durand line is the border between India and Afghanistan. [ ]
Answer:
1. True
2. False
3. True
4. False
5. True
6. True
7. True
8. False
9. False
10. True
11. True
12. True
13. False
14. False
15. True

Match the following : 1 Mark

Name of border	Lying between countries
i. LOC	(a) India and Bhutan
ii. MC Mohan	(b) India and Nepal
iii. Palk Strait	(c) India and Sri Lanka
iv. Indo-Burma Barrier	(d) India and Afghanistan
v. Radcliff line	(e) India and Pakistan
vi. Purvachal	(f) India and Myanmar
vii. Durand line	(g) India and Bangladesh
viii. Indo-Bhutan	(h) India and China

Answer:

Name of border	Lying between countries
i. LOC	(e) India and Pakistan
ii. MC Mohan	(h) India and China
iii. Palk Strait	(c) India and Sri Lanka
iv. Indo-Burma Barrier	(f) India and Myanmar
v. Radcliff line	(b) India and Nepal
vi. Purvachal	(g) India and Bangladesh
vii. Durand line	(d) India and Afghanistan
viii. Indo-Bhutan	(a) India and Bhutan

Answer in few words : 1 Mark

Question 1.
Name the great mountain wall or the northern boundary of India.
Answer:
The Himalayan range.

Question 2.
In which hemisphere does India lie?
Answer:
North Eastern hemisphere.

Question 3.
Which is the smallest state of India ?
Answer:
Goa.

Question 4.
From which state was Jharkhand formed?
Answer:
Bihar.

Question 5.
Which is the youngest state of India?
Answer:
Telengana.

Question 6.
Which is the smallest Union Territory?
Answer:
Lakshadweep.

Question 7.
Name the countries that bound the north west of India.
Answer:
Pakistan and Afghanistan.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 4 Waste Management offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 4 Question Answer – Waste Management

Answer in short : 2 Marks

Question 1.
What do you mean by waste ?
Answer:
‘Waste’ refers to items that we don’t need and we discard. They may be harmful to the environment and are non-usable.

Question 2.
Name some types of wastes.
Answer:
Some types of wastes are : solid wastes, liquid wastes, gaseous wastes, toxic wastes, non-toxic wastes etc.

Question 3.
Name some wastes that come from households.
Answer:
Wastes generated in households are remains of vegetables, fruits etc., scales and bones of fishes, polythene packets, broken bottles, plastic containers, tin containers, aluminium foils, excess food items etc.

Question 4.
What are solid wastes?
Answer:
Solid wastes are any type of garbage or rubbish that are generated at home and outside. They may include food wastes, newspapers, broken household and office items, old car tyres etc.

Question 5.
What are liquid wastes ?
Answer:
Liquid wastes include wash waters from homes, cleaning liquids used in industries, waste detergents etc. Sometimes solid wastes are converted to liquids before discarding.

Question 6.
What are gaseous wastes ?
Answer:
Gaseous wastes can result from activities like manufacturing, processing of materials, consumption or other biological processes. Eg- CO₂, SO₂, N₂, NH₃ etc.

Question 7.
What are toxic wastes ?
Answer:
Toxic wastes are hazardous, harmful and poisonous to public health and environment. Eg. Old propane tanks, pesticides, mercury containing equipments, lamps, batteries etc.

Question 8.
What are non-toxic wastes ?
Answer:
Non-toxic wastes are not so seriously harmful to public health and environment. They can be easily decomposed. Eg – Domestic wastes, food left-overs, fruits and vegetable peelings, paper, wastes produced by shops, restaurants and schools.

Question 9.
What do you mean by industrial wastes ?
Answer:
The wastes produced by industries manufacturing glass, leather, textile, food, electronics, plastic, metal products etc. are called industrial wastes.

Question 10.
What are agricultural wastes?
Answer:
Agricultural wastes are typical produced by agricultural activities like horticulture, fruit growing, seed growing, livestock breeding, market gardening etc. Apart from biotic wastes, they also include non-biotic wastes like pesticide containers, out- of-date medicines, cocoa pods etc.

Question 11.
What are the different processes of waste management?
Answer:
The different processes of waste management are – reduction, reuse and recycling.

Question 12.
Name some methods by which waste can be disposed.
Answer:
The various methods by which wastes can be disposed are – (i) Dumping on open grounds, (ii) Burning, (iii) Landfilling, (iv) Composting, (v) Manure pit, etc.

Question 13.
What are hazardous wastes?
Answer:
The wastes that harmed the environment and the biotic world dangerously, are called hazardous wastes. Ex – (i) Harmful chemical, (ii) Radio-active wastes, (iii) Infected items discarded from hospitals, etc.

Question 14.
Name some diseases that can spread from solid wastes.
Answer:
Some diseases that can spread from solid wastes are – dysentry, skin diseases, worms, typhoid, tuberculosis, jaundice, tetanus, hepatitis, eye diseases, lung diseases etc.

Question 15.
What do you mean by bio-degradable wastes?
Answer:
The wastes that can be reduced and degraded easily by biological entities are called bio-degardable wastes. Generally, the plant and animal wastes are biodegradable. Ex-Proteins, nucleic acids etc. can be degraded by certain bacteria.

Question 16.
What are non bio-degradable wastes ?
Answer:
The wastes that cannot be reduced or degraded by any biological entity are called non bio-degradable wastes. Ex.- Plastic, glass, polythene etc.

Question 17.
What do you mean by waste management?
Answer:
Waste management is the method of collecting wastes scientifically, segregating them, taking steps for recycle, re-use and reduction, so that the ultimate damage or pollution caused by the wastes comes down to minimum.

Question 18.
What is dumping ?
Answer:
Dumping is the process of discarding wastes (usually from large municipal regions) in a lowland, a little away from the main city.)

Question 19.
What are nuclear wastes?
Answer:
The wastes generated from nuclear reactors, raw materials used in nuclear plants, radio-active elements discarded from nuclear plants, etc. are called nuclear wastes. They are highly reactive and very dangerous.

Question 20.
What is Pyrolysis ?
Answer:
The process by which fuel is obtained from solid wastes by processing them in absence of oxygen, is called pyrolysis.

Question 21.
Name four bio-degradable wastes.
Answer:

1. Vegetable peels
2. Bones of fishes and meat
3. Pieces of newspaper
4. Pieces of cotton cloth.

Question 22.
Name two infectious diseases.
Answer:
(i) Influenza, (ii) Hepatitis – B.

Question 23.
What is Landfilling ?
Answer:
The mehtod of discarding wastes in approved grounds, filling up the huge holes dug to bury the wastes, is called Landfilling.

Question 24.
What is Composting ?
Answer:
The bio-degradable wastes are separated and reduced by machines. Then they are degraded with the help of bacteria in order to create humus. The way biotic material produced is called compost, and the process of preparing this is called composting.

Question 25.
What are the most common bad effects of wastes ?
Answer:
Wastes spread bad smell and cause environmental pollution. They help to spread infectious diseases.

Answer in brief : 3 Marks

Question 1.
Name some sources of wastes.
Answer:
Some sources that generate wastes are :

1. Household, hospitals, markets, municipalities etc.
2. Small business centres.
3. Discarded materials from non-producing or abundant factories.
4. Construction materials.
5. Agriculture and food processing.
6. Atomic research centres etc.

Question 2.
Differentiate between toxic and non-toxic wastes.
Answer:

Toxic wastes	Non-toxic wastes
i. Amount of toxic wastes in the environment is less (10%).	i. Amount of non-toxic wastes in the environment is more (90%).
ii. They usually come from hospital wastes, old propane tanks, pesticides, lamps, batteries etc.	ii. They usually come from households.
iii. They are harmful and poisonous.	iii. They are not poisonous and are less harmful.
iv. They may cause infectious diseases. Toxic wastes	iv. They usually do not cause infections. Non-toxic wastes

Question 3.
Differentiate between bio-degradable and non-biodegradable wastes.
Answer:

Bio-degradable wastes	Non-biodegradable wastes
i. Complex biotic materials are converted to simple biotic materials.	i. Wastes cannot be converted to simple substances.
ii. Generated from plant and animals wastes.	ii. Generated from sources other than plants and animals.
iii They are degraded by microorganisms like bacteria.	iii. They are degraded by high temperature and pressure.
iv. Eg-wood, paper, kitchen wastes, food remains etc.	iv. Eg-polythene, PVC, pastic, DDT etc.

Question 4.
What are ‘manure pits’?
Answer:
‘Manure pits’ are hollows dug in the ground in rural areas in order to decompose bio-degradable wastes. The household wastes are thrown into these pits along with some cowdung. These wastes start decomposing and are converted into biotic manure that are used for agriculture.

Question 5.
What do you mean by landfilling ?
Answer:
Landfilling is the most common method of waste disposal, where the waste is buried underground. But this method is not much in use in modern days, as this required a huge vacant land for this purpose, produces strong methane and other gases and cause contamination problems.

Question 6.
Mention some cases where solid wastes are recycled.
Answer:
Solid wastes recycling helps in conservation of resources, controls environmental pollution and also reduces the cost of production. some examples of recycling soild wastes are :

1. Fly ash : Fly ash generated in thermal power stations are used for producing cement, filling up low lands and building low dams.
2. Fibres of sugarcane, agricultural wastes etc. : These are used to produce pulp for paper industies.
3. Plastic, metals, glass, paper etc. : These are melted or processed to be used as raw materials in the respective industries.

Question 7.
Name the methods by which waste materials can be managed and put to use.
Answer:
The main methods of waste management are :

1. Reduction : This refers to the process of waste minimisation at the source itself.
2. Re-use : Items like packing boxes, papers, toys, old clothes etc. can be used again and again, thus saving raw materials, money, controlling pollution and environmental degradation.
3. Recycling : This refers to processing of used materials into new useful products, thus saving raw materials and resources. Eg – paper, metal, plastic and glass items.

Question 8.
What is the need for waste management ?
Answer:
A proper waste management system is urgently needed for the following reasons –

1. To control different types of pollution.
2. To stop the spread of infectious diseases.
3. To conserve environmental resources including forests, minerals, water etc.
4. To recycle hazardous wastes for further production.

Question 9.
What are the advantages and disadvantages of Sanitary landfill?
Answer:
Advantages –

• The wastes are buried underground. Hence they spread less air pollution.
• The gases emitted in this process are used to prepare fuels.
• Biotic fertilisers are obtained by composting of the biotic wastes under pressure.

Disadvantages –

• By landfilling, the polluted water from the wastes gradually percolate underground and get mixed with ground water.
• Disposal of wastes in lowlands hamper the ecosystem and reduce agricultural lands.

Question 10.
What do you mean by Bio-remediation?
Answer:
Bio-remediation is the newest method of waste management. This is the method where bio-technology is used to generate several microbes and fungi. These are applied on biotic wastes so that they can be reduced to the lowest forms. This is a faster process of reducing biotic wastes. It was first applied in 1990 . But the method is not absolutely perfect and suitable for waste management. Ex.- This method is not applicable for all kinds of biotic wastes. Also, the oxygen, nitrogen, phosphorus and other chemicals required by the microbes have to be supplied artificially from outside.

Question 11.
What is Sludge?
Answer:
Different kinds of solid wastes get deposited in drains and sewage pipes, especially in municipal areas. The huge pieces of solid wastes are filtered out with nets. The pieces that are suspended in the sewage water are transfered to large tanks. Calcium carbonate is added to this sewage water, by which the suspended solid wastes settle down at the bottom of the tanks. These deposits at the bottom of the tanks is known as Sludge.

Question 12.
What do you mean by re-use of wastes?
Answer:
The way that the wastes can be used once again in some productive and useful way is called Re-use of wastes. Example of Re-use of wastes can be listed as follows –

1. Biotic fertilisers and biogas : Vegetable peels and other biotic wastes from households and localities can be used to produce bio-fertilisers and biogas.
2. Sugarcane fibre: Huge amounts of sugarcane fibre are re-used to produce paper pulp for paper industries.
3. Old newspapers : Old newspapers, books and copies can be used to produce paper pulp for paper, cardboard, etc.
4. Plastic : Old plastic items can be melted to produce new plastic items.
5. Glass : Discarded glass can be re-used to make new glass. It is also used as a substitute of asphalt.
6. Fly ash : Fly ash can be used for filling up low lands and making bricks.

Question 13.
What do you mean by recycling?
Answer:
The method by which old items are used once again to produce the same item is called recycling. Ex-paper, glass, plastic, metals etc. But the materials produced after recycling is lesser in amount than the initial waste material used.

Question 14.
What is Scrubber? Or what is Scrubbing?
Answer:
Scrubbing is the process of removal of wastes from gases. The gases filled with solid wastes are passed through water. This makes the waste particles wet and heavy. Thus they gradually settle down at the bottom of the containers and waste free gas/air is released. Scrubbing is useful for removing suspended solid wastes from gas/air upto 99 \%.

Answer in details : 5 Marks

Question 1.
Classify the different kinds of wastes.
Answer:
Different types of wastes are as follows:
(i) Solid wastes : Solid wastes are any type of garbage or rubbish generated at home or outside. Eg- food wastes, newspaper, broken household articles etc.
(ii) Liquid wastes : Liquid wastes include wash waters from homes, cleaning liquids used in industries, waste detergents etc. Sometimes, solid wastes are converted to liquids before discarding.
(iii) Gaseous wastes : Gaseous wastes include CO₂, SO₂, N₂O, NH₃ etc. produced as a result of manufacturing activites, consumption and other biological processes.
(iv) Toxic wastes : Toxic wastes are harmful and hazardous poisonous wastes that threaten public health and environment. Eg – pesticides, mercury containing equipments, lamps, batteries etc.
(v) Non-toxic wastes: These wastes are not poisonous as such and do not pose a serious problem to the environment. They can be decomposed easily. e.g. domestic wastes, food left-overs, paper, glass etc.

Question 2.
What are the different sources of wastes?
Or
Classify wastes according to their sources.
Answer:
Wastes can be classified according to sources as :
(i) Domestic wastes : These are wastes generated by household activities. Eg – food left-overs, empty containers, carry bags etc.
(ii) Industrial wastes: These are wastes produced by manufacture works in industries like glass, leather, textile, food, electronics, plastic, metal etc.
(iii) Agricultural wastes: These are typically produced by agricultural activities like horticulture, fruit growing, seed growing, livestock, breeding, market, gardening etc. Non-biotic wastes like pesticide containers, out-of-date medicines etc. are also generated.
(iv) Municipal wastes: These include trash or garbage from households, schools, offices, markets, restaurants and other public places.
(v) Organic wastes : These wastes come from animal or plant sources. EgVegetable peels, garden trimming etc.
(vi) Bio-medical wastes: These wastes come from hospitals and clinics. Egused injection syringes, cotton, bandages, surgical items, body parts etc.
(vii) Radioactive wastes: These wastes contain radioactive materials generated as by-products of nuclear power generation. Eg-Buring of uranium fuel in nuclear reactors.

Question 3.
Discuss the effects of waste disposal on the environment.
Answer:
The effects of waste disposal on several parts of the environment are discussed below :
(a) Effect of solid wastes : (i) Solid wastes lying on ground for a long time pollutes the soil and water of the region. (ii) Diseases like typhoid, jaundice, cholera, dysentery, titanus, skin problems, worms, lung diseases etc. may spread.
Bad smell may spread and cause air pollution.

(b) Effect of toxic wastes : (i) Toxic materials cause air, water and soil pollution. (ii) Toxic materials spread into the food web and enter our bodies causing nerve diseases, kidney problems, tumours, genetic problems, cancer, ulcer etc.

(c) Effect of chemical wastes : Chemical wastes coming from pesticides, insecticides etc. tend to reduce nitrogen content of soil, thus reduce fertility. (ii Numerous animals and birds may get killed. (iii) Land may become totally unproductive.

(d) Effect on water : Accumulation of wastes in rivers, lakes, ponds, oceans, etc. causes death of numerous aquatic plants and animals. (ii) Fishes loose reproductive capacities. (iii) Water ecosystems may get disrupted.

(e) Effect on air : Air pollution increases in alarming rates.

(f) Effect on soil : (i) Wastes disposed on grounds change the chemical properties of soils. (ii) Soils may become acidic and salty and unfit for vegetation growth.

Question 4.
Discuss the methods of waste management.
Answer:
The common methods of waste management are :
(i) Reduction : This is a process of waste minimisation at the source itself, and elimination of harmful and persistant wastes. This involves re-designing of products in order to reduce production of wastes at home, work or other places.
(ii) Reuse : To reuse is to use an item again after it has been used before. Reuse helps to save time, money, energy and resouces. Eg- packing boxes, gift wrapers, toys etc.
(iii) Recycling : Recycling is processing used materials into new, useful products. It helps to save raw materials, energy and money and controls pollution and environmental degradation. Eg – newspaper, metal and glass items etc.

Question 5.
Discuss the several processes of waste disposal and management.
Answer:
The different processes of waste disposal and management are :
(i) Segregation of wastes : Separation of wastes at source of collection is known as segregation of wastes. This reduces the cost of transportaion, energy and helps in acquiring organic stock for energy generation. Wastes may be categorised as: (a) Bio-degradable : Kitchen wastes, garden trimmings, paper etc. (b) Non-biodegradable : Plastics, glass, old medicines, containers etc.

(ii) Landfilling : This is the most common and old method of waste disposal where the waste is buried underground. But this method is not in much use in modern days as it requires huge vacant lands, produces strong methane and other gases and cause contamination problems.

(iii) Composting : This is the process by which unsafe organic wastes are turned into safe organic products with the help of microbes. Eg – organic fertilisers produced from kitchen and food wastes.

(iv) Drainage method : This is a method of removal of suspended solid waste particles in disposed fiquids or water before it is discharged back to the environment.

(v) Scrubbing : Wet scrubbing is a method of using a liquid to remove solid, liquid or gaseous wastes and pollutants. The scrubbing liquid is sprayed into the disposed gas in a spray chamber. Contact with the spray liquid removes the particulate pollutants of the gas. Dry scrabbing is also a popular method.

Question 6.
What is the need for waste management ?
Answer:
A proper waste management system is urgently required for the following –

1. To control different types of pollution.
2. To control the spread of infectious diseases.
3. To conserve environmental resources like forests, minerals, water etc.
4. To recycle hazardous wastes for further production.

Question 7.
What is the role of students in waste management ?
Answer:
Effective waste management is best achieved at household level, and students can take an active role in this process. They can take up the following steps :
(a) Reduce waste creation : (i) Use towels and ceramic plates instead of paper napkins and disposable plates. (ii) Use biodegradable shopping bags instead of plastic bags. (iii) Use old packing boxes and gift wraps.
(b) Reuse things : (i) Use old clothes from elders. (ii) Use old toys, gift wraps, furniture etc. (iii) Innovative use of discarded items. Eg – penstand out of soda cans.
(c) Cleaning programmes : (i) Awareness camps and demonstration programmes regarding garbage disposal.(ii) School can arrange groups of students for regular survery, whether the local people are following cleaning and garbage disposal systems or not.

Question 8.
Discuss the effects of waste disposal in the Bhagirathi- Hooghly river.
Answer:

Waste disposal in huge amounts in the Bhagirathi – Hooghly river pollutes the water in alarming scales. The main sources of pollutants are :

1. Disposal of sewage waters from large cities located on the river side.
2. Disposal of wastes from industries.
3. Agricultural wastes from chemical fertilisers, insecticides etc.
4. Washing of animals, disposal of dead bodies, toilets etc. in river water.
5. Immersion of idols, washing clothes and utensels etc. in river water.
6. Disposal of hot water from thermal power stations etc.

All these actions make the river water impure, which is unhygenic for drinking, domestic, agricultural or industrial use.

Multiple Choice Questions (MCQ) : 1 Mark

Question 1.
The method of using a liquid to remove wastes is called –
(A) Composting
(B) Scrubbing
(C) Dumping
(D) Landfilling
Answer:
(A) Composting

Question 2.
The primary treatment of wastes removes about _______ % of suspended solids from the water –
(A) 20 %
(B) 30 %
(C) 60 %
(D) 70 %
Answer:
(C) 60 %

Question 3.
4R factor for waste management are –
(A) Reproduction-Response-Recover-Record
(B) Reduce-Refuse-Reuse-Recycle
(C) Regenerate-Renew-Reintroduce-Restart
(D) Repeat-Reforms-Reuse-Reproduction
Answer:
(B) Reduce-Refuse-Reuse-Recycle

Question 4.
Hazardous and harmful wastes are called –
(A) Non-toxic
(B) Solid
(C) Toxic wastes
(D) None of these
Answer:
(C) Toxic wastes

Question 5.
The wastes those come from plant or animal sources are called –
(A) Inorganic wastes
(B) Industrial wastes
(C) Organic wastes
(D) Radioactive wastes
Answer:
(C) Organic wastes

Question 6.
Food wastes, fruit and vegetables peels, garden triminings etc. are-
(A) Industrial wastes
(B) Inorganic wastes
(C) Bio-medical wastes
(D) Organic wastes
Answer:
(D) Organic wastes

Question 7.
The liquid that forms as water trickles through contaminated areas is called-
(A) Leachate
(B) Gaseous wastes
(C) Solid wastes
(D) Industrial wastes
Answer:
(A) Leachate

Question 8.
Plastics, glass, old medicines, bulbs, cans etc. are examples of –
(A) Bio-degradable
(B) Non-biodegradable
(C) Organic wastes
(D) Bio-medical wastes
Answer:
(B) Non-biodegradable

Question 9.
Leachate is –
(A) Very healthful mixture of chemicals
(B) Very useful mixture of chemicals
(C) Very resourceful mixture of chemicals
(D) Very harmful mixture of chemicals
Answer:
(D) Very harmful mixture of chemicals

Question 10.
Kitchen wastes, garden trimmings, paper etc. are examples of –
(A) Non-biodegradable
(B) Bio-degradable
(C) Solid wastes
(D) Gaseous wastes
Answer:
(B) Bio-degradable

Question 11.
The place where the waste is buried underground-
(A) Composting place
(B) Landfilling
(C) Segregation of waste
(D) Drainage method
Answer:
(B) Landfilling

Question 12.
Secondary waste treatment removes about –
(A) 30 % of the waste
(B) 50 % of the waste
(C) 70 % of the waste
(D) 90 % of the waste
Answer:
(D) 90 % of the waste

Question 13.
Burning of Uranium in nuclear reactors create –
(A) Radioactive
(B) Toxic
(C) Biomedical wastes
(D) None of these
Answer:
(A) Radioactive

Question 14.
Separation of wastes at source of collection is known as –
(A) Landfilling of wastes
(B) Segregation of wastes
C) Composting of wastes
(D) Scrubbing
Answer:
(B) Segregation of wastes

Question 15.
Useless things, produced in everyday life is known as –
(A) Garbage
(B) Rubbish
(C) Wastes
(D) Pollutant
Answer:
(C) Wastes

Question 16.
DDT, chemical fertilizers, fungicides weedicides etc. examples of –
(A) Biological wastes
(B) Industrial wastes
(C) Chemical wastes
(D) Municipal wastes
Answer:
(C) Chemical wastes

Question 17.
Among biomedical wastes the amount of infectious wastes is –
(A) About 20-22 %
(B) About 30-32 %
(C) About 10-12 %
(D) About 5-10 %
Answer:
(C) About 10-12 %

Question 18.
An example of Bio-nonanalytical organic material is –
(A) Protein
(B) Glass
(C) Nucleic Acid
(D) None of these
Answer:
(B) Glass

Question 19.
The depth of the soil layer above the sanitary landfill is –
(A) 2 metre
(B) 3 metre
(C) 4 metre
(D) 6 metre
Answer:
(A) 2 metre

Question 20.
It takes time to become organic or bio-fertilizer in manure pit –
(A) 2-4 months
(B) 3-4 months
(C) 4-5 months
(D) 1 year
Answer:
(A) 2-4 months

Question 21.
Fungus can be used as-
(A) Control of pests
(B) Weedicide
(C) Element of improving land fertility
(D) None of these
Answer:
(B) Weedicide

Question 22.
Every year amount of land in the world being transformed into desert –
(A) 80 lakh hectare
(B) 30 lakh hectare
(C) 40 lakh hectare
(D) 20 lakh hectare
Answer:
(C) 40 lakh hectare

Question 23.
Main cause of concern on impact in extensive agriculture is –
(A) Chemical fertilizer
(B) Pesticide
(C) Irrigation
(D) Capital
Answer:
(B) Pesticide

Question 24.
Integrated Pest Management is –
(A) Control of pests by chemical pesticides
(B) Destruction of pest infested plants
(C) Integrated application of different methods of pest control
(D) None of the above
Answer:
(C) Integrated application of different methods of pest control

Question 25.
In the biological control process of pests –
(A) Biofertilizer is used in agriculture
(B) Bacteria, virus, fungus
(C) Use of weedicides of control crop pests
(D) None of the above
Answer:
(B) Bacteria, virus, fungus

Question 26.
The full form of NCEP –
(A) National Commission for Environmental Protection
(B) National Committee on Environment Planning
(C) National Committee on Environment Protection
(D) None of the above
Answer:
(B) National Committee on Environment Planning

Question 27.
The permissible limit of pH in drinking water is –
(A) 6.5 – 8.5
(B) 3.5 – 5.5
(C) 4.5 – 6.5
(D) 7.5 – 8.5
Answer:
(A) 6.5 – 8.5

Question 28.
The Government of India had set up a separate ministry for environment for environment in the year –
(A) 1980
(B) 1975
(C) 1990
(D) 2000
Answer:
(A) 1980

Fill in the blanks : 1 Mark

1. The bombing on Hiroshima-Nagasaki is an example of _______ wastes.
2. Old newspaper is a _______ waste.
3. The landfill process leads to the formation of _______ gas.
4. In a scrubber, the wastes one managed by _______.
5. Black foot disease occurs due to _______ pollution.
6. Pesticide is an _______ waste.
7. _______ is celebrated as world Environment Day.
8. The use of already discarded wastes is termed as _______.
9. _______ wastes can be managed by decomposition by microorganisms.
10. _______ is the process of disposing wastes in large pits dug in the ground.
11. _______ wastes are used to produce fuel gas.
12. _______ is used to make paper.
13. A sharp medical waste is _______.
14. Motor oil is a _______ waste.
15. The atomic energy plants generated _______ waste.
16. The animal remains is a _______ waste.
17. Fly ash is a _______ waste.
18. Radium is a _______ waste.
19. Water coming out after washing wastes in landfall method is called _______.
Answer:
1. Radioactive
2. Biodegradable
3. Ammonia
4. Friction
5. Arsenic
6. Agricultural
7. 5th June
8. Re-use
9. Biodegradable
10. Land filling
11. Biotic
12. Sugarcane
13. Surgical knife
14. Liquid
15. Radioactive
16. Biotic
17. Hazardous
18. Radioactive
19. Leachate

State True or False : 1 Mark

1. Minimising the amount of wastes is called reduction. [ ]
2. Electronic wastes are also called e-wastes. [ ]
3. BOD refers to Biological Oxygen Demand. [ ]
4. Sorting of dry and moist wastes is called extraction. [ ]
5. Radiation coming from X-ray machines do not cause radioactive pollution. [ ]
6. Fluoride overuse leads to fluorosis. [ ]
7. Disposal of wastes on high open lands is called dumping. [ ]
8. The Central Ganga Authority was formed in 1985. [ ]
9. Fly ash came from hydel power stations. [ ]
10. Infectious wastes come from hospitals. [ ]
Answer:
1. True
2. True
3. True
4. False
5. False
6. True
7. False
8. True
9. False
10. True

Answer in few words : 1 Mark

Question 1.
What are wash-waters from homes and industries, cleaning liquid etc. called ?
Answer:
Liquid wastes.

Question 2.
What are hospital and clinical wastes called ?
Answer:
Biomedical wastes.

Question 3.
What are wastes coming from plants and animals called ?
Answer:
Organic wastes.

Question 4.
What is Municipal wastes ?
Answer:
Garbage coming from households, schools, offices, markets, restaurants etc.

Question 5.
Name a toxic waste material.
Answer:
Mercury.

Question 6.
Give an example of non-biodegradable material.
Answer:
Polythene.

Question 7.
Name a source of air pollution.
Answer:
Burning of dangerous wastes.

Question 8.
What kind of wastes are radioactive materials ?
Answer:
Toxic wastes.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 3 Hydrosphere offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 3 Question Answer – Hydrosphere

Answer in short : 2 Marks

Question 1.
What are ocean currents?
Answer:

A continuous and regular horizontal movement of ocean water in a fairly defined direction over a great distance on the surface or sub-surface of the ocean is called ocean currents.

Question 2.
How many types of ocean currents are there?
Answer:
There are two types of ocean currents : warm current and cold current.

Question 3.
What is a Sargasso sea ?
Answer:
In the North Atlantic Ocean, the warm gulf current, the cold canary current and the warm north equatorial current flow in a circular pattern.
The water trapped in between these currents remains still and stagnant. A vast growth of moss and other small plants are seen here.This region is known as the Sargasso sea.

Question 4.
What are sand bars?
Answer:
When the warm and cold currents meet, the icebergs being carried by the cold current melts and the sand, pebbles etc. that were within the iceberg gets deposited at the base, creating sand bars. These are economically very useful, as low depth of the sea near the sand bars attract much fishes that are easily acquirable.

Question 5.
Mention two advantages of ocean currents.
Answer:
(i) Ocean currents help in navigation of ships.
(ii) A huge amount of planktons are available in the region where warm and cold currents meet. These attract huge amount of fishes and help in growing of fishing grounds.

Question 6.
Mention two disadvantages of ocean currents.
Answer:
(i) The meeting of warm and cold currents gives rise to huge amount of fog and may create stormy weather.
(ii) The icebergs that flow along with cold currents create a lot of trouble for sailing ships.

Question 7.
What is a tide?
Answer:
The sea water rises in the gulfs and at sea-coasts regularly twice a day at regular intervals. This periodic phenomena of alternate rise and fall in level of the seas is known as Tides.

Question 8.
Mention the causes of tides.
Answer:
The causes of tides are :

1. Gravitational pull of the moon.
2. Effect of Centrifugal force due to rotation of the earth.
3. Gravitational pull of the sun.

Question 9.
What are sea waves?
Answer:
The vertical movement of sea water due to force exerted by wind blowing on the surface, without any horizontal displacement of the water particles is called sea waves. In sea waves, the water moves only up and down.

Question 10.
What are the different controlling factors of ocean currents?
Answer:
The controlling factors of ocean currents are :
(i) Wind, (ii) rotation of the earth, (iii) temperature, density and salinity of ocean water and (iv) presence and location of landmasses.

Question 11.
How does wind cause ocean currents ?
Answer:
The planetary winds blowing over the oceans in fixed directions throughout the year are the main causes of ocean currents. The winds push the water of the oceans in particular directions creating currents. About 2-4% of wind energy is used to create ocean currents. Eg.- The monsoon winds control the flow of ocean currents in the Indian Ocean.

Question 12.
Which ocean shows seasonal reversal of ocean currents and why?
Answer:
The Indian Ocean shows seasonal reversal of ocean currents. Due to the commencement of monsoon winds, the ocean currents flow from south to north and during retreat of the monsoon winds the currents flow from north to south. Thus, there is a 180° reversal of flow of ocean currents during the season change.

Question 13.
What is an ‘Ice wall’?
Answer:
In the Atlantic ocean, near the islands of Newfoundland, the deep green water of the cold Labrador current coming from the north, pass the deep blue water of the warm gulf stream side by side. The boundary of these two currents can be seen very clearly, which looks like an ice wall.

Question 14.
Name two famous sand bars of the world.
Answer:
(i) Grand Bank near Newfoundland in North America.
(ii) Dogger’s Bank in the British Isles of England.

Question 15.
What is the gulf stream ?
Answer:

The part of the North Atlantic current that crosses the Carribean sea and Gulf of Mexico, is called the Gulf stream. It is a warm current (27°C) of deep blue waters.

Question 16.
What is the Grand Bank?
Answer:
Grand Bank is a huge sandbar created near Newfoundland in North America in the northwestern part of the Atlantic Ocean. It is about 96,000 sq . km. in area and its depth is less than 90 ~m. It is a famous fishing ground of the world.

Question 17.
What is the Labrador current?
Answer:

• Labrador current is the ocean current generated from the Arctic ocean due to the polar winds.
• This cold current flows along the western coast of Greenland (between Greenland and Canada) towards the south and flows further to the south along the eastern coast of Labrador Peninsula.

Question 18.
Name some important warm currents of the North Atlantic ocean.
Answer:
Some important warm currents of the North Atlantic Ocean are : (i) North Equatorial current, (ii) Carribean current, (iii) Gulf Stream, (iv) North Atlantic current, (v) Norway current etc.

Question 19.
Name some important cold currents of the North Atlantic Ocean.
Answer:
Some important cold currents of the North Atlantic ocean are : (i) Labrador current, (ii) Eastern Greenland current, (iii) Canary current, (iv) Arctic current etc.

Question 20.
Name some important warm currents of the South Atlantic Ocean.
Answer:
Some important warm currents of the South Atlantic Ocean are : (i) South Equatorial current, (ii) Brazil current, (iii) Guinea current etc.

Question 21.
Name some important cold currents of the South Atlantic Ocean.
Answer:
Some important cold currents of the South Atlantic Ocean are : (i) Antarctic current, (ii) Benguela current, (iii) Folkland current etc.

Question 22.
Name the different warm currents of the Pacific Ocean.
Answer:
Some warm currents of the Pacific ocean are : (i) East Australian current (ii) North and South Equatorial current (iii) Kuroshio current (iv) North Pacific current (v) Alaska current etc.

Question 23.
Name the different cold currents of the Pacific Ocean.
Answer:
The cold currents of the Pacific Ocean are : (i) Antarctic current (ii) Humbolt current (iii) California current (iv) Bering current (v) Kamchatka current etc.

Question 24.
Name some important warm currents of the Indian Ocean.
Answer:
Some important warm currents of the Indian Ocean are : (i) North Equatorial current (ii) South Equatorial current (iii) Madagascar current (iv) Agulhas current (v) Somali current etc.

Question 25.
Name some important cold currents of the Indian Ocean.
Answer:
Some important cold currents of the Indian Ocean are : (i) Antarctic Ocean current (ii) West Australian current etc.

Question 26.
Which currents meet near the Japan coast that helps in creation of fishing grounds?
Answer:
The warm Kuroshio current and the cold Kurile current meet near the coast of Japan, that helps in the formation of fishing grounds.

Question 27.
How does the temperature of ocean water influence the flow of ocean currents?
Answer:
Temperature of ocean water influences the flow and direction of ocean currents. The equatorial and tropical regions being warm, make the water of the adjacent ocean warm as well. The water remains lighter and tends to flow outward towards the poles. This vacuum thus created is filled up by incoming cold currents from the polar regions.

Question 28.
Why is the Japan coast prone to cyclones frequently?
Answer:
The meeting of the warm Kuroshio current and the cold Bering current are responsible for occurrence of frequent cyclones on the coast of Japan.

Question 29.
Why does the British Isles coastal region remain frost free while the Labrador coast remains frozen, inspite of both lying on the same latitude?
Answer:
The warm North Atlantic current flowing along the Western coast of the British Isles helps to keep the region frost free inspite of lying on the same high latitudes as the Labrador coast.

Question 30.
What is the importance of the warm gulf stream of the North Atlantic Ocean?
Answer:

1. The Gulf stream creates foggy conditions and storms near the coastal areas of Newfoundland.
2. It keeps the coastal regions of Norway and British Isles frost free.
3. It helps in creation of fishing grounds on the sandbar of Grand Bank near Newfoundland.
4. It helps in navigation and creation of ice walls.

Question 31.
What is a primary tide or Direct tide?
Answer:
The tide produced in front of the moon is called a Direct tide or Primary tide. Ocean water of the earth nearest to the moon are attracted more strongly. It happens when the moon is directly overhead and its strong attraction forces the water to pile up on that place to form high tide.

Question 32.
What is Secondary or Indirect tide?
Answer:
During high tide, piling of water takes place even at the antipode of the side facing direct tides. This is known as secondary or Indirect tide.

Question 33.
What is a Spring tide?
Answer:
Twice in a month, i.e. on New moon and Full moon days, the moon, the earth and the sun come in a straight line. The combined gravitational forces of the sun and moon cause the highest of high tides. This is called a Spring tide.

Question 34.
What is a Neap tide?
Answer:
When the sun and the moon lie at right angles to each other, the gravitational forces of both counteract each other. Thus the tidal range becomes comparatively low. This is called a Neap tide.

Question 35.
What is a Tidal Bore?
Answer:
When a tide enters the narrow and shallow estuary of a river, the front of the tidal wave appears to be vertical, owing to the piling up of water of the river against the tidal wave and friction against the river bed. The steep-nosed tide crest looks like a vertical water of water rushing upstream. This is called a Tidal Bore.

Question 36.
What causes the occurrence of Tidal Bores?
Answer:
Tidal bores may occur due to :

1. Funnel shape of the mouth of the river.
2. Presence of sandbars near the mouth of the river.
3. Tremendous current of the river water.

Question 37.
What is the interval between two high tides?
Answer:
The interval between two high tides is about 12 hours 24 minutes 44.5 seconds.

Question 38.
What is the interval between a high tide and a low tide ?
Answer:
The interval between a high tide and low tide is about 6 hours 12 minutes 22.25 seconds.

Answer in briefly : 3 Marks

Question 1.
Differentiate between waves and ocean currents.
Answer:

Waves	Ocean currents
i. This refers to the upward and downward movement of sea water.	i. This refers to the horizontal movement of sea water.
ii. The water moves up and down but no big displacement of the water occurs.	ii. The water flows through a specific path or direction horizontal to the surface of the sea.
iii. Created due to wind movement, vulcanism, earthquake etc.	iii. Created due to planetary winds, temperature of water, salinity, presence of landmass, rotational speed of the earth etc.
iv. Moves perpendicular to the alignment of coasts.	iv. Moves parallel to the alignment of coasts.
v. Useful for marine erosion and deposition.	v. Useful for carrying away the eroded materials.
vi. Does not influence weather and climate.	vi. Influences weather and climate.

Question 2.
How do prevailing winds influence ocean currents ?
Answer:
Ocean currents are mainly caused by prevailing winds. The planetary winds push the surface layers of ocean water towards a constant flow. If, due to seasonal change, the direction of wind is changed, the currents also have a similar change in their direction.
In Tropical regions, equatorial currents moves from east to west under the influence of trade winds. In Temperate regions, the westerlies drive the sea water from west to east.

Question 3.
What is the influence of difference in temperature of sea water on ocean currents?
Answer:
Temperature is low at the poles and high at the equator. The polar water is cool, heavy and sinks while the equatorial water is warm, light and floats. This sets up convectional currents in the ocean. Warm water of the equatorial regions are light and move along the surface towards the polar regions where they are cooled.

Question 4.
What is the influence of salinity of ocean water in formation of ocean currents?
Answer:
The salinity of ocean water varies from place to place. Water of high salinity are denser than water of low salinity. Hence water of low salinity flow on the surface while water of high salinity flows at the bottom towards water of low salinity.

Question 5.
How does the centrifugal force influence ocean currents?
Answer:
The centrifugal force at the equator is greater than that at the poles. Due to this variation of forces, the equatorial water moves towards the poles.

Question 6.
How does evaporation and rainfall influence ocean currents?
Answer:
Evaporation reduces the amount of water in the ocean and increases salinity. Rain water raises the sea level and reduces salinity. This difference between density of water caused by evaporation and rainfall helps to generate ocean currents.

Question 7.
How does the shape of the continents influence ocean currents ?
Answer:
The ocean currents generally follow the coastline of the continents while flowing. But presence of numerous islands in their way may bifurcate the currents into numerous smaller streams of ocean currents.

Question 8.
What are Primary and Secondary tides?
Answer:
The tides produced on the surface of the earth facing the moon are called primary tides or Direct tides. At the same time, there is a piling of ocean water on the antipode or the opposite side of the earth. These tides are called Secondary or Indirect tides.

Question 9.
What are spring tides?
Answer:
The term Spring tides comes from the German word ‘Springen’, which means to jump. Twice a month, at new moon and full moon, the sun, the earth and the moon fall in straight line. The combined gravitational pull of the sun and the moon causes the highest tides. These are known as Spring tides.

Question 10.
What are Neap tides?
Answer:
Neap tides occur when the sun and the moon lie at right angles to the earth. This happens in the first and last quarters of the moon. The gravitational force of the sun and the moon counteracts each other. The tidal range is neither too high nor too low. These tides are known as neap tides.

Question 11.
What is Syzygy?
Answer:
When the sun, the moon and the earth come along the same straight line, this fact is known as syzygy in astrology. Two types of positions are found in syzygy:
(i) Conjunction : At the time of Full Moon, when the earth comes between the moon and the sun in a straight line the position is called conjunction.
(ii) Opposition : At the time of New Moon, when the moon comes between the earth and the sun in the same line, this position is known as opposition.

Question 12.
What are Perigean tides and Apogean tides?
Answer:

Perigean tides : When the moon is the closest to the earth (354,330 km), this position is known as perigee. The perigee position increases the attracting force of the moon and the tide is extraordinarily high. This is known as Perigean tide.
Apogean tides : When the moon is farthest from the earth (4,03,320 km), this position is known as Apogee. Due to reduced attraction of the moon, the tide is also 20% less high. This is known as Apogean tide.

Question 13.
Mention the characteristics of ocean currents.
Answer:
The characteristics of ocean currents are :

1. The warm currents flow outwards from the equatorial region towards the polar region.
2. The cold currents flow inwards from the polar region to the equatorial region.
3. The ocean currents flow almost in the same direction as the direction of the prevailing winds.
4. Speed of ocean currents is higher in shallow water and slower in deep water.

Question 14.
How does the centrifugal force of the earth influence the creation of tides?
Answer:
Centrifugal force is generated due to the rotation of the earth. Due to this force, all particles tend to move outward in the opposite direction of the gravitational force. Thus, the water present on the earth’s surface always tends to rise and move in the opposite direction of gravitational force. This leads to the creation of tides in different parts of the earth.

Question 15.
Why high tides and low tides each occur twice a day ?
Answer:
The earth (each and every part) faces the moon after every 24 hours 49 minutes 29 seconds. The side that faces the moon experiences direct or primary high tides and the opposite side experiences indirect or secondary high tides. Again, as the earth rotates, the place which experienced primary high tide will now experience secondary high tide and vice versa. The time difference between primary and secondary tides is 12 hours 24 minutes 44.5 seconds. The places lying at right angles to places experiencing high tides will experience low tides. Hence, two low tides occur in each place. Thus we see that both high tides and low tides occur twice a day.

Answer in details : 5 Marks

Question 1.
Discuss the causes of ocean currents.
Answer:

The main causes of the origin of ocean currents are:
(a) Prevailing winds : The planetary winds or prevailing winds push the surface layers of the ocean water in front of them in a constant flow. If, due to a seasonal change, the direction of wind is changed, the currents also have a similar change in their direction. In Tropical areas, the equatorial currents moving along with trade wind move from east to west. In Temperate regions, westerlies drive the sea water from west to east.
(b) Difference in temperature: Temperature is low at the poles and high at the equator. The polar water is cool and becomes heavy and sinks. Te equatorial water is warm, light and floats. This creates a convectional current and the polar water move towards the equator and vice versa.
(c) Difference in salinity : The salinity of ocean water varies from place to place. Water of high salinity are denser than water of low salinity. Hence, water of low salinity flows on the surface while water of high salinity flows at the bottom of the oceans.
(d) Rotation of the earth : The rotation of the earth generates a centrifugal force, which causes generation of currents in the ocean water.
(e) Shape of coasts : The shape and direction of the coasts of the landmasses also change the direction of the currents.
(f) Centrifugal force : The centrifugal force of the earth is greater at the equator than the poles. Hence, water currents move from equatorial region to the poles.
(g) Evaporation and rainfall : Evaporation decreases water level and increases salinity while rainfall increases the water level and decreases salinity. This influences the flow of ocean currents.
(h) Melting of ice : Melting of ice raises the sea level and reduces salinity, influencing the ocean currents.

Question 2.
List the general characteristics of ocean currents.
Answer:
The characteristics of ocean currents are as follows:

1. The general movement of ocean currents is clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.
2. Warm currents move towards cold seas and cold currents move towards warm seas.
3. In the lower latitudes, the warm currents flow on the eastern shores and cold currents in the western shores. This condition is reversed in the higher latitudes.
4. Convergence and divergence of warm and cold currents influence the direction of flow.
5. The shape and position of continents guide the direction of ocean currents.
6. The currents flow not only at the surface, but also below the sea surface.

Question 3.
What are the effects of ocean currents ?
Answer:
The various effects of ocean currents are:
i. Difference in temperature : The regions where warm ocean currents pass, become comparatively warmer, while the regions where cold ocean currents pass, become comparatively cooler.
ii. Rainfall : Winds crossing warm ocean currents gather enough moisture and cause much rainfall. But winds causing cold currents do not gather much moisture, hence do not cause much rainfall.
iii. Fog and Storms : Regions where warm and cold currents meet remain foggy almost throughout the year and often face storms.
iv. Parity in temperature: The ocean currents help to balance the distribution of heat of the water between higher and lower latitudes. Hence they influence distribution of world temperature.
v. Frost-free harbours : Warm currents help to keep the mouths of the harbours of higher latitudes frost-free even in winters.
vi. Navigation : Ships can move faster and easily along the ocean currents. Movement against the direction of currents is difficult, time consuming and fuel consuming.
vii. Sandbars : When warm and cold currents meet, the icebergs carried by cold currents melt. The sand, pebbles etc. being carried by the icebergs get deposited at the base, creating sandbars. These are economically useful as low depth of the sea in this region attracts much fishes which can be easily acquired.
viii. Business and commerce : Sandbars are good for growth of planktons, which are favourite fish foods. Thus huge number of fishes are attracted to these regions. This leads to a huge catch of fish, naturally leading to good business and commerce.

Question 4.
Discuss the causes of tides.
Answer:

The main causes of tides are –
i. Gravitational pull of the moon : Although both the sun and the moon exert gravitational force on the earth, the sun’s force is only 46 \% of that of the moon due to its large distance from the earth compared to the moon. Hence, the moon’s influence on the tides is twice as strong as that of the sun. The water of the earth nearest to the moon is pulled by its gravitational force. This makes the water on this side bulge, causing high tide. Waters on the opposite side also experience high tides at a comparatively lower scale. The areas perpendicular to these areas experience ebb or low tides.

ii. Effect of centrifugal force or rotation of the earth : Rotation of the earth causes generation of centrifugal force, which tends to throw the waters outwards. This causes the rise of water as tides.
iii. Gravitational pull of the sun : The sun also helps to cause tides. When it lies in the same side as the moon, it causes very big tides. When the sun lies in the opposite direction to the moon, it causes weaker tides.

Question 5.
Discuss the effects of tides.
Answer:
The various effects of tides are :

1. Tidal energy can be harnessed to generate electricity.
2. Fishermen’s activities are controlled by the rhythms of high and low tides.
3. Tidal water helps ships to move in and out of river ports.
4. Tides help to increase depth of channels, lower freezing points at river mouths, help to clear depositions at river mouths and clear sewage from large urban centres.
5. During high tides low lying areas along sea coasts are flooded and this water is trapped for production of salt.
6. Tides aid the destruction of coastline and help to move debris to the sea.
7. Bores are characteristics of certain river mouths, such as those of the Amazon, Colorado, Hooghly and Elbe.
8. When bores are well-developed, the moving wall of water may be 4-5 m high and is reported to be a terrifying and destructive phenomenon.

Question 6.
Why the time difference between two primary high tides of the same place is about 24 hours 49 minutes?
Answer:
The earth takes about 23 hours 56 minutes 48 seconds to complete one rotation. If the moon would have been fixed, the same place of the earth would have experienced primary high tides after every 23 hours 56 minutes 48 seconds. But as the moon is revolving in its orbit in 27 \(\)\frac{1}{3}\(\) days in the same direction due to earth’s rotation, the conditions change. As the speed of earth’s rotation and moon’s revolution are not the same the moon covers (360° ÷ 27 \(\)\frac{1}{3}\(\). day) = 13° 10′ 14.63″ angular distance every day. Therefore, the moon takes extra time of (13° 10’14.63″ × 4. minutes) = 52 minutes 41 seconds to reach the same place once again. For this, the time difference of primary high tides at a particular place of two following days is about 24 hours 49 minutes 29 seconds.

Multiple Choice Questions (MCQ) 1 Mark

Question 1.
Water movement is –
(A) Vertical
(B) Horizontal
(C) Vertical and horizontal
(D) None of these
Answer :
(B) Horizontal

Question 2.
Waves are caused due to –
(A) Winds
(B) The moon and the sun
(C) Tides
(D) Ocean currents
Answer :
(A) Winds

Question 3.
On the new moon, occurs the –
(A) Spring tide
(B) Neap tide
(C) Ebb tide
(D) Low tide
Answer :
(A) Spring tide

Question 4.
Warm ocean currents flow towards the –
(A) Polar regions
(B) Equatorial regions
(C) Tropical regions
(D) Temperate regions
Answer :
(A) Polar regions

Question 5.
At the places where warm and cold currents meet, occurs –
(A) Cyclones
(B) Tides
(C) Clear sky
(D) Dense fog
Answer :
(D) Dense fog

Question 6.
Cold water is seen in –
(A) Pacific Ocean
(B) Atlantic ocean
(C) Indian ocean
(D) Arctic ocean
Answer :
(B) Atlantic ocean

Question 7.
Warm currents flow along the –
(A) Low latitudinal or Equatorial region
(B) Middle latitudinal region
(C) High latitudinal region
(D) Polar region
Answer :
(A) Low latitudinal or Equatorial region

Question 8.
The El-Nino which influences the Indian monsoon is –
(A) A cold ocean current that flows northwards along the coast of Chile
(B) A warm ocean current that flows westwards
(C) A low pressure system over western coast of Spain
(D) None of these
Answer :
(D) None of these

Question 9.
What is the interval between high tides at a place ?
(A) 12 hour
(B) 12 hour 26 minute
(C) 15 hour 30 minute
(D) 24 hour
Answer :
(B) 12 hour 26 minute

Question 10.
The place lying opposite to the moon experiences –
(A) Low tide
(B) Primary tide
(C) Secondary tide
(D) No tide
Answer :
(C) Secondary tide

Question 11.
Neap tide occurs on the – day after the new moon and full moon.
(A) 5 th
(B) 6th
(C) 7 th
(D) 8 th
Answer :
(D) 8 th

Question 12.
The South and North Equatorial currents of Atlantic Ocean move from east to west by the influence of –
(A) Trade winds
(B) Westerlies
(C) Polar winds
(D) Local winds
Answer :
(A) Trade winds

Question 13.
The direction of ocean currents is reversed with seasons in the –
(A) Pacific Ocean
(B) Atlantic Ocean
(C) Indian Ocean
(D) Arctic Ocean
Answer :
(C) Indian Ocean

Question 14.
Average salt content in 1 litre of sea water is –
(A) 39 gm
(B) 37 gm
(C) 35 gm
(D) 32 gm
Answer :
(C) 35 gm

Question 15.
The water in the oceans move horizontally over vast areas due to –
(A) Slope of the sea floor
(B) Waves
(C) Difference in density
(D) Currents
Answer :
(C) Difference in density

Question 16.
The tide at its maximum height is known as –
(A) Primary tide
(B) Neap tide
(C) Spring tide
(D) Ebb tide
Answer :
(C) Spring tide

Question 17.
The factors responsible for the movement of the surface oceanic currents are –
(i) Prevailing winds
(ii) Earth’s rotation
(iii) Earth quake
(iv) Difference in density of sea water
(v) Sea floor topography
(A) i, iii and iv
(B) i, ii and iii
(C) i, iii and iv
(D) None of these
Answer :
(A) i, iii and iv

Question 18.
Dense fog is formed near Newfoundland and Grand Bank due to convergence of –
(A) Cold Labrador current and warm gulf stream
(B) Cold Canary current and warm gulf stream
(C) Cold Labrador current and warm kuroshio current
(D) None of these
Answer :
(A) Cold Labrador current and warm gulf stream

Question 19.
The position of smallest distance between the earth and the moon is called –
(A) Apogee
(B) Perigee
(C) Apogean
(D) None of these
Answer :
(B) Perigee

Question 20.
High tides are caused when –
(A) The sun, earth and moon lie in a straight line.
(B) The sun and moon lie perpendicular to the earth
(C) Both ‘A’ and ‘B’
(D) None of these
Answer :
(A) The sun, earth and moon lie in a straight line.

Question 21.
High tides are caused at the time of-
(A) Fullmoon
(B) New moon
(C) Both ‘A’ and ‘B’
(D) None of these
Answer :
(C) Both ‘A’ and ‘B’

Question 22.
High tides are also called –
(A) Neap tides
(B) Spring tides
(C) Ebb tides
(D) Primary tides
Answer :
(B) Spring tides

Question 23.
The sun, the moon and the earth are in position of opposition during the-
(A) New moon
(B) Full moon
(C) Half moon
(D) Crescent moon
Answer :
(B) Full moon

Question 24.
The position of the sun, moon and earth in a straight line is called-
(A) Syzygy
(B) Quadrature
(C) Opposition
(D) None of these
Answer :
(A) Syzygy

Question 25.
When the earth lies inbetween the sun and the moon, the position is called –
(A) Conjunction
(B) Opposition
(C) Quadrature
(D) None of these
Answer :
(B) Opposition

Question 26.
When the sun, earth and moon lie in a position of right angle, it is called-
(A) Opposition
(B) Conjunction
(C) Quadrature
(D) None of these
Answer :
(C) Quadrature

Question 27.
During neap tides, the sun, earth and moon come in the position of-
(A) Opposition
(B) Quadrature
(C) Syzygy
(D) Conjunction
Answer :
(B) Quadrature

Question 28.
The position of farthest distance between earth and moon is called –
(A) Apogee
(B) Perigee
(C) Conjunction
(D) Opposition
Answer :
(A) Apogee

Question 29.
Cold wall is seen in
(A) Atlantic
(B) Antractic
(C) Indian
(D) Pacific Ocean
Answer :
(A) Atlantic

Question 30.
Which of the following is an warm current ?
(A) Kamchatka
(B) Peru
(C) Brazil
(D) West Australian
Answer :
(C) Brazil

Question 31.
Ocean currents are generated due to
(A) Difference in temparature
(B) Difference in Salinity
(C) Movements of Planetary winds
(D) All the above is correct
Answer :
(C) Movements of Planetary winds

Question 32.
The speed of ocean current in shallow seas compared to deep seas is
(A) More
(B) Less
(C) Not affected
(D) Remain same
Answer :
(A) More

Question 33.
Grand bank is a
(A) Warm Current
(B) Cold Current
(C) Submerged bar
(D) Island
Answer :
(C) Submerged bar

Question 34.
Ocean currents created by
(A) Rotation of the earth
(B) revolution of the earth
(C) Gravitational force
(D) None of these
Answer :
(A) Rotation of the earth

Fill in the blanks : 1 Mark

1. The general movement of a mass of oceanic water in a definite direction is called ________.
2. Okhotsk current is found in the _________ ocean.
3. _______ currents help in the formation of Sargasso sea.
4. _________ current is characterised by high temperature and high salinity.
5. ________ current is also known as Humboldt current.
6. North-east monsoon currents are produced between Andaman and ________.
7. El-Nino is a weather event restricted to certain ________ areas.
8. El-Nino maximum affects the ________ coast.
9. Fall of sea water and its movement towards the sea is called an ________.
10. Each day, tide is delayed by _______ minutes.
11. Perigean tides are ________ percent higher than the normal tides.
12. The coasts of British Isles and Norway remain frost-free due to the influence of the _______ current.
13. The _______ winds control the currents of the Indian Ocean.
14. The largest sand bar of the world is the ________.
15. The Madagascar and Mozambique currents combine to form the ________ current.
16. The warm _________ current keeps the east coast of Japan warm in winter.
17. ________ is created at the meeting points of warm and cold currents.
18. Heavy saline water flows as ________.
19. The average speed of ocean current is ________.
20. ________ is the largest ocean of the world.
21. The colour of water in the ________ current is slightly greenish.
22. The floating blocks of ice in the ocean are called ________.
23. The ice wall can be seen in the _______ Ocean.
24. The Sargasso Sea has been created in the _______ Ocean.
25. Planktons concentrate where ________.
Answer:
1. Ocean current
2. Pacific
3. Artiles
4. Brazil
5. Peru
6. Somali
7. Tropical
8. Peruvian
9. Ebb
10. 26
11. 15-20
12. Warm gulf stream
13. Monsoon
14. Grand Bank
15. Aguthas
16. Kuroshio
17. Fog
18. Under current
19. 5-10 km/ hr.
20. Pacific Ocean
21. Labrador
22. Ice bergs
23. Atlantic
24. Atlantic
25. Warm and Cold Currents meet

State True or False : 1 Mark

1. Benguela current flows through the Indian Ocean. [ ]
2. The ocean curents get deflected due to coriolis force. [ ]
3. The cold oyashio current flows along the coast of Japan. [ ]
4. Grand Bank lies in the Pacific Ocean. [ ]
5. Meeting of warm and cold ocean currents lead to the formation of fog. [ ]
6. Bering current is a cold current in the North Pacific Ocean. [ ]
7. Labrador current is a cold current in the North Atlantic Ocean. [ ]
8. A warm current flowing through the south Pacific Ocean is the New South Wales current. [ ]
9. A cold current flowing through the South Pacific Ocean is the Peru current. [ ]
10. The rising and falling of ocean water is known as ocean current. [ ]
11. The Humboldt current follows the coast of Chile. [ ]
12. The warm gulf stream lowers the temperature of the Eastern coast of North America in winter. [ ]
13. The meeting of the warm Kuroshio current and the cold Oyashio current lead to formation of dense fog and stormy conditions along the Japan coast. [ ]
14. The Western coast of the continents in tropical regions are influenced by cold curents, which lead to lack of rainfall and formation of deserts. [ ]
15. Ebb tides occur on new moon and full moon nights. [ ]
16. Tidal bores occur in the lower course of the river Hugli. [ ]
17. The ocean currents in the southern hemisphere are deflected towards the left due to rotation of the earth. [ ]
18. The Sargasso sea has no current. [ ]
19. Kuroshio current is a warm current. [ ]
20. California current is a cold current. [ ]
21. Foggy weather persist near the cold wall. [ ]
22. Drought occure along the east coast of Pacific ocean under the influence of La Nina. [ ]
Answer:
1. False
2. True
3. True
4. False
5. True
6. True
7. True
8. True
9. True
10. False
11. True
12. False
13. True
14. True
15. False
16. True
17. True
18. True
19. True
20. True
21. True
22. True

Answer in few words : 1 Mark

Question 1.
How much of the earth’s surface is covered by oceans?
Answer:
About 3 / 4 th.

Question 2.
What is the tide caused on full moon called ?
Answer:
Spring tide.

Question 3.
Which ocean currents move towards polar regions ?
Answer:
Warm ocean currents.

Question 4.
What type of ocean currents originate in high latitudes?
Answer:
Cold currents.

Question 5.
Which ocean currents have lighter water ?
Answer:
Warm currents.

Question 6.
Which ocean currents have denser water?
Answer:
Cold currents.

Question 7.
What is the direction of flow of ocean currents in the northern hemisphere?
Answer:
Clockwise.

Question 8.
What is the other name of Low tide?
Answer:
Ebb tide.

Question 9.
How many tides occur in a day?
Answer:
Two high tides and two low tides.

Question 10.
What is the upward and downward movement of ocean water called?
Answer:
Ocean waves.

Question 11.
Which is the main controlling power of the ocean current?
Answer:
Planetary wind.

Question 12.
In which ocean Sargasso sea is seen ?
Answer:
Atlantic ocean.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 2.5 Humidity and Precipitation offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 2.5 Question Answer – Humidity and Precipitation

Answer in short : 2 Marks

Question 1.
What do you mean by ‘Hydrological cycle’?
Answer:
Water is present on the earth’s surface as well as the atmosphere in different forms. This water is transported from one sphere to the other in different forms in a cyclical pattern. This circulation of water from lithosphere (earth’s surface or underground) to atmosphere and back is known as the hydrological cycle. It is mainly driven by evaporation and condensation.

Question 2.
What do you mean by humidity ?
Answer:
Humidity is the general term refering to the water vapour content of air at one time and place. It is the measure of the dampness of the atmosphere.

Question 3.
What is the relation between humidity and temperature ?
Answer:
Humidity capacity or moisture retaining capacity of air is directly related to the temperature condition of the air. Higher the temperature, greater is the water holding capacity of air and vice versa. Hence, cooler air gets saturated faster than hot air.

Question 4.
What do you mean by saturation of air ?
Answer:
Air is said to be saturated when it holds moisture or water vapour to its fullest capacity at that particular temperature.

Question 5.
What do you mean by Absolute humidity ?
Answer:
Absolute humidity refers to the total amount of water vapour present in a given volume of air. It is the weight of actual amount of water vapour present in a unit volume of air. It is measured in gram per cubic centimetre.

Question 6.
What is Relative humidity ?
Answer:
The ratio of the amount of water vapour present in the air mass at a given temperature of a place to the maximum quantity that the air can hold at that particular temperature, is known as relative humidity.

Question 7.
What is Specific Humidity ?
Answer:
Specific humidity is the mass of water vapour in grams contained in a kilogram of air. It represents the actual quantity of moisture in a definite amount of air. It is measured in gram/kilogram.

Question 8.
What is condensation?
Answer:
The process of conversion of atmospheric water vapour back to water is known as condensation. In the atmosphere, they may occur in the forms of dew, fog, smog, cloud, mist, haze etc.

Question 9.
What is the ‘Dew point’ ?
Answer:
The temperature at which air gets saturated and below which condensation begins is called the ‘Dew point’.

Question 10.
What is ‘dew’?
Answer:
The water droplets formed by the condensation of water vapour on a relatively cold surface is called ‘dew’.

Question 11.
What is the difference between fog and smog?
Answer:
Suspended tiny droplets or ice crystals in the air layer next to the earth, that reduce visibility to 1000 m or even lower are called fog. Combination of smoke with fog, which creates a hazy environment, reducing visibility even more, is called smog. It is more common in an industrial areas.

Question 12.
What is cloud?
Answer:
A visible aggregate of tiny water droplets or ice crystals or a mixture of both suspended in the air, are called cloud. It forms when condensation meets with supersaturation conditions within the air that is free from dust and aerosols.

Question 13.
What do you mean by Precipitation?
Answer:
Condensation of water vapour in the air in the form of water droplets and ice, and their falling on the ground is called precipitation. It can occur in the form of rain, snow, sleet, hail etc.

Question 14.
What is rainfall ?
Answer:
When moisture-laden air rises up, condensation takes place and clouds are formed. It the clouds air further cooled, more condensation occurs and drops of water formed are big in size. These big water drops are too heavy to remain in the air and fall down towards the ground in liquid form. This is called rainfall.

Question 15.
What is an isohyet?
Answer:
An isohyet is an imaginary line drawn on a map joining places receiving the same amount of rainfall in a given period, such as a month, a season or a year.

Question 16.
Name the different types of rainfall.
Answer:
There are three types of rainfall-convectional, orographic or relief and cyclonic or frontal rainfall.

Question 17.
Where does convectional rainfall generally occur?
Answer:
Convectional rainfall is very common in the Equatorial region where it occurs almost daily in the afternoon around 4 o’clock. Hence, it is also called the 4 o’clock rain.

Question 18.
What do you mean by climatic regions ?
Answer:
The average weather conditions of a particular region during a particular period of the year, recorded for 35 years is known as climate. Depending on the predominant climate, the world can be divided into several regions. These regions are called the ‘Climatic regions’.

Question 19.
How can you identify wet equatorial climate prevailing in a region?
Answer:
The conditions that prove the existence of wet equatorial climate prevailing in a region are :

1. Average temperature : 25°-29°C
2. Average annual rainfall : 250 cm, rainfall occurs in all the months.
3. Maximum rainfall : occurs in March-April, and September – October.

Question 20.
How can you identify Tropical Monsoon climate?
Answer:
The conditions of Tropical Monsoon climate are :

1. Average annual temperature : 24°C
2. Average summer temperature : 27°-32°C
3. Average winter temperature : 10°-27°C
4. Average rainfall : 100-150 cm
5. Highest rainfall : May to September in northern hemisphere, November to March in southern hemisphere.

Question 21.
How can you identify Tropial Hot Desert climate?
Answer:
The conditions of Tropical Hot Desert climate are :

1. Average annual temperature : 20°-32°C
2. Average annual rainfall : 16-25 cm
3. Hottest months : May to August in the northern hemisphere, November to February in the Southern hemisphere.

Question 22.
How can you identify Mediterranean climate?
Answer:
The conditions of Mediterranean climate are :

1. Average annual temperature : 13°-18°C
2. Average summer temperature : 14°-22°C
3. Average winter temperature : 10°-14°C
4. Average annual rainfall occuring during winter : 35-75 cm

Question 23.
How can you identify Tundra climate?
Answer:
The conditions of Tundra climate are :

1. Average annual temperature : (-) 10°C to (-) 15°C
2. Average annual rainfall : 10-15 cm. Most precipitation occurs in the form of snow.
3. Hottest months : May to August in the northern hemisphere and November to February in the Southern hemisphere.

Question 24.
Mention two characteristics of absolute humidity.
Answer:
(i) Absolute humidity may remain unchanged throughout the day even if Relative Humidity changes.
(ii) Absolute humidity helps to decide the amount of precipitation possible.

Question 25.
Name the instruments that help to measure humidity.
Answer:
Humidity can be measured by the Dry and Wet Bulb Thermometer. It is also measured by a Hygrometer. The common types of Hygrometers used for this purpose are – Dew point Hygrometer, Hair Hygrometer, Resistant Hygrometer etc.

Question 26.
Why is fog and smog more common in urban and industrial areas ?
Answer:
The air over urban and industrial areas is filled with suspended particles of dust, carbon etc. which act as a cool surface for condensation of water vapour. Thus, they cause occurrence of fog and smog much more in urban and industrial areas.

Question 27.
Name the regions of the world that experience Hot Wet Equatorial climate.
Answer:
The regions that experience Hot Wet Equatorial climate are :

1. Amazon basin in Brazil, South America.
2. The Zaire basin, Congo basin, Ivory coast, Ghana, Nigeria in Africa.
3. Malaysia, Indonesia and other islands of South-East Asia.

Question 28.
Name some countries that experience tropical monsoon climate.
Answer:
The countries that experience tropical monsoon climate are – (i) India, (ii) Pakistan, (iii) Bangladesh, (iv) Myanmar, (v) Cambodia, (vi) Thailand, (vii) Laos, (viii) Vietnam etc.

Question 29.
Name some hot deserts of the world.
Answer:
(a) Africa – Sahara, Kalahari
(b) Asia – Arab, Thar
(c) North America – Colorado, Soneran
(d) South America – Atacama, Peru
(e) Oceania – The Great Australian desert

Question 30.
Name some important Temperate grasslands of the world.
Answer:

1. Steppes of Europe and Asia (World’s largest)
2. Prairies of North America.
3. Pampas of South America
4. Veld of Africa
5. Downs of Oceania.

Question 31.
Why is the Equatorial region called ITCZ ?
Answer:
The Equatorial region is called the ITCZ or the Inter Tropical Convergence Zone because the South-Eastern and North-Eastern trade winds meet at the Equatorial region near 5°-10° N and S latitudes.

Question 32.
Why is the Equatorial region called Doldrums?
Answer:
The Equatorial region does not face any wind due to the convergence of the trade winds of both the hemispheres. A condition of calm persists in this region. This is called Doldrums.

Question 33.
Why is Equatorial rainfall also called 4 o’clock rainfall ?
Answer:
The Equatorial region experiences convectional rainfall. The sky remain clear and bright throughout the day. But due to high rates of evaporation, dense cumulonimbus clouds accumulate at about 3-4 o’clock in the afternoon and cause heavy rainfall. Thus, it is also called 4 o’clock rainfall.

Question 34.
What is a temperature and rainfall graph ?
Answer:
Temperature and rainfall graph is a type of composite thematic map, where the average monthly temperature is represented by the line graph and the total monthly rainfall is represented by bar graphs on the same graph paper. It helps to compare and analyse the temperature and rainfall conditions of a place at the same time.

Answer in brief : 3 Marks

Question 1.
What is the importances of water vapour in the atmosphere?
Answer:
The importances of water vapour in the atmosphere are –

1. Water vapour absorbs some insolation as well as back radiation of earth’s heat. Thus, it reduces atmospheric temperature to a certain extent.
2. It releases latent heat while condensation and may increase temperature to a certain extent.
3. Without water vapour, precipitation of no kind would have been possible (rain, snow, dew, fog etc.)
4. Too much presence of water vapour makes the atmospheric condition very humid and uneasy.
5. It influences growing of certain industries like cement, jute and flour.

Question 2.
Compare between Absolute Humidity and Relative humidity.
Answer:

Absolute Humidity	Relative Humidity
i. Represents the total or absolute amount of water vapour present in the unit volume of air at that particular temperature.	i. Represents the ratio between the present amount of water vapour and the total amount of water vapour that the unit volume of air can hold at that particular temperature.
ii. It is an absolute amount.	ii. It is a ratio.
iii. It is expressed in ‘grams’.	iii. It is expressed in percentage.
iv. It can remain constant throughout the day.	iv. It changes with change in atmospheric temperature in a day.
v. Does not give any idea whether rainfall may occur or not.	v. Gives an idea whether rainfall may occur or not.

Question 3.
How is rainfall measured ?
Answer:
Rainfall is measured with the help of an instrument called ‘Rain Gauge’. The rain gauge is planted till its half in the ground in an open space, where the rain water can directly fall into the instrument. This collected water is then poured into a measuring cylinder to record the amount of rainfall. It is expressed in millimetres or inches. Nowadays, a self-recording instrument called the ‘Hyetograph’ is used for measuring rainfall.

Question 4.
What is a rain-shadow area ?
Answer:
In maintainous areas, the moisture-laden clouds hit with the windward slope and shed the rains over there. The opposite or leeward slope of the mountain does not receive much or any rainfall. This drier slope of the mountain is called the rain-shadow area.

Question 5.
List the major climates of the world and their average annual temperature and rainfall conditions.
Answer:

Climate	Average annual temperature	250 cm
i. Wet equatorial climate	25°-27° C	100-150 cm
ii. Tropical Monsoon climate	25° C	below  16 cm
iii. Hot desert climate	30°-35° C	35-75 cm
iv. Mediterranean climate	13°-18° C	25-50 cm
v. Steppe Climate	16°-20° C	100-150 cm
vi. China Climate	27° C in summer 4° C in winter	250 cm (West)
vii. West coast Oceanic climate	16° C in summer, 4° C in winter	75 cm (East)
viii. West continental climate	20°-25° C in summer Below 0° C in winter	50-100 cm
ix. Wet temperate climate	10° C in summer Below 0° C in winter	25-50 cm
x. Tundra climate	-12° C	10-40 cm

Question 6.
What are the controlling factors of relative humidity?
Answer:
The controlling factors of relative humidity are –

1. Temperature – Temperature is inversely related to relative humidity. If temperature increases, water holding capacity of air increases, hence humidity decreases.
2. Water vapour – Increase in amount of water vapour in the air increases relative humidity.
3. Rainfall – Increase in rainfall is the result of increase in relative humidity.
4. Air pressure – Relative humidity is usually higher in regions of low pressure.

Answer in details : 5 Marks

Question 1.
Discuss the Convectional rainfall.
Answer:

Rainfall which is caused due to convectional currents in the atmosphere is called convectional rainfall. Excessive heating causes too much evaporation. Thus air is filled with water vapour. This heated and light air rises upwards until temperature reduces and reaches its dew point. The water vapour then condenses and forms

cumulus clouds. They further develop into cumulo-nimbus clouds at about 11 \mathrm{km} height. These clouds are very heavy and bring about rainfall, usually accompanied by thunder and lighting. These are also called Thunder showers. Convectional rainfall is most common in the Equatorial region, where it occurs almost daily in the afternoon around 4 o’clock. Hence, they are also called the 4 o’clock rains.

Question 2.
Discuss the occurrence of Orographic or Relief rainfall.
Answer:
When the moisture-laden winds blowing from sea strike against mountains, the humid winds rise up along the windward slope. As they rise, they cool down and bring heavy rainfall to the windward slope. Such a rain by uprising winds striking against mountains is called orographic (‘oro’- greek word meaning mountain) or Relief rainfall. Eg : Rainfall occuring on the southern slopes of the Himalayas.

Question 3.
Discuss the occurrence of cyclonic or frontal rainfall.
Answer:
The rainfall associated with the passage of a cyclone or depression is known as Cyclonic rainfall. It is formed where a warm air mass overrides a cold air along a front. When the warm and cold air masses move towards each other, the

warm air being lighter ascends over the cold air along the front. This leads to cooling the air, condensation and rainfall. Cyclonic rainfall occuring in Tropical regions is heavy and intense. Rainfall associated with Temperate cyclones is much lighter and less intense.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 2.4 Pressure Belts and Winds offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 2.4 Question Answer – Pressure Belts and Winds

Answer in short : 2 Marks

Question 1.
What do you mean by air pressure?
Answer:
The pressure exerted by the column of air of the atmosphere lying above a unit area of the earth’s surface is called air pressure.

Question 2.
What is an altimeter?
Answer:
Altimeter is an instrument for measuring altitude. It also measures air pressure along with altitude. It is commonly used by pilots, mountaineers etc.

Question 3.
What is a Fortin’s Barometer?
Answer:

Fortin’s Barometer is an instrument most commonly used for measuring atmospheric pressure. It is provided with a main scale and a vernier scale to measure air pressure with most accuracy.

Question 4.
What is an isobar?
Answer:
Isobars are imaginary lines drawn on weather maps joining places having same air pressure at a particular time of the year, considering the places to be at the mean sea level.

Question 5.
What is pressure gradient?
Answer:
The slope between the physical distance of two places and their pressure differences is known as the pressure gradient.

Question 6.
What are pressure belts ?
Answer:
The zones of the earth which exhibit similar pressure conditions on an average in circular belts according to the latitudes are called pressure belts. They can be either high pressure belts or low pressure belts.

Question 7.
What are pressure troughs?
Answer:
Although the entire earth is divided into pressure zones, some areas may exhibit a little different pressure conditions than their surroundings. These areas may be enclosed with certain isobars. Such circular zones of pressure conditions are called pressure troughs.

Question 8.
Mention the factors on which difference of air pressure depends.
Answer:
The air pressure conditions depend on the following factors :

1. Temperature of the wind.
2. Altitude of the place.
3. Amount of water vapour in the air.
4. Rotation of the earth.
5. Depth or height of the air column above the place.
6. Distribution of land surface and water bodies etc.

Question 9.
What is wind and air current?
Answer:
The horizontal movement of the air from high pressure regions to low pressure regions is known as wind. The vertical movement of air above the earth’s surface is known as air current.

Question 10.
State Ferrel’s law.
Answer:
Ferrel’s law states that due to the coriolis force created by the rotation of the earth, the winds are deflected towards the right in the northern hemisphere and towards the left in the southern hemisphere.

Question 11.
What is a Beufort scale?
Answer:
Beufort scale is a scale designed by Sir Francis Beufort, to measure the energy of wind. It is marked from 0-12. ‘0’ refers to a calm state of wind and ’12’ refers to a highly destructive and ferocious tornado.

Question 12.
What are roaring forties ?
Answer:
The roaring forties are extremely powerful westerly winds that blow in the southern hemisphere between latitudes 40°-50°. These gale-force, west to east currents are the result of the combination of three variables : warm air movements, the earth’s rotation and near absence of relevant landmasses in southern hemisphere.

Question 13.
What is Loo?
Answer:
The ‘Loo’ is a strong, dusty, hot and dry summer wind from the west which blows over the Indo-Gangetic plain of North India and Pakistan. It is mainly blows in Summer (May to June). Due to its very high temparature, exposure to it often leads to total heat strokes.

Question 14.
What is Buys Ballot’s law ?
Answer:
In the Northern Hemisphere, if a person stands with his back to the wind the atmospheric pressure is low to the left, high to the right. This is because, wind travels anticlockwise around low pressure belt in the Northern Hemisphere, and is reversed in the Southern Hemisphere.

Question 15.
What is Geostrophic wind ?
Answer:
In the condition of Geostrophic equilibrium, a thin wind stream is generating when pressure gradient force and coriolis force come into exact balance. It is a upper layer atmospheric wind.

Question 16.
What is an anemometer?
Answer:
Anemometer is an instrument used to measure wind speed.

Question 17.
What are planetary winds?
Answer:
The earth has certain fixed high pressure and low pressure belts that lie paralle] to the equator. This generates winds blowing from high to low pressure regions in fixed directions throughout the earth. These winds that blow regularly in specific directions throughout the year are called planetary winds.

Question 18.
What are trade winds?
Answer:
Winds that blow from the subtropical hight pressure belts or horse latitudes (30°-35° north and south) to the low pressure belts or doldrums (5°N-5°S) are known as the Trade winds.

Question 19.
Why are trade winds so called ?
Answer:
Trade winds blow over the region of the earth which has much landforms and large population. In early days, the sailors used to sail their ships with the help of the trade winds for trade and business from one continent to another. Hence the winds are called ‘Trade winds’.

Question 20.
What are westerlies?
Answer:
The winds that blow from sub-tropical high pressure belts towards the sub-polar low pressure belts are called westerlies. They blow towards the poles generally from south-west in the northern hemisphere and from the north-west in the southem hemisphere. As they blow from the west in both the hemispheres, they are called westerlies.

Question 21.
What are polar winds?
Answer:
The winds that blow from the high pressure region of poles towards the sub-polar low pressure zones are called polar winds. Since they blow from the east in both the hemispheres, they are also called Polar Easterlies.

Question 22.
What are periodic winds ?
Answer:
Some winds that blow for a limited period of a day or time to time or for a certain season of the year are called periodic winds. Eg. – sea breeze, land breeze, monsoon winds etc.

Question 23.
What is sea breeze?
Answer:
During day time, the wind that blows from sea towards the land is known as sea breeze. This happens due to unequal heating of land and sea and difference in pressure conditions thus created.

Question 24.
What is land breeze?
Answer:
During the night, the wind that blows from land towards the sea is called land breeze. This is because of the unequal rates of radiating heat by land and sea after sunset, hence creating a difference in pressure conditions over the land and sea surfaces.

Question 25.
What are local winds ?
Answer:
There are certain type of winds which are produced by local temperature differences created due to local topographic landform. These winds are called local winds, and their zone of influence is also very small. Eg. – Sirocco, Loo etc.

Question 26.
What are sudden or irregular winds ?
Answer:
Intense heating or cooling of land and sea sometimes develop severe low pressure centre or centre of high pressure. It brings about irregular winds of great or mild speed. These are called sudden or irregular winds. They do not have any routine time of occurrence.

Question 27.
What is a cyclone?
Answer:

Cyclones are stormy whirls of wind. They come suddenly with great force and velocity towards the centre of low pressure. Cyclone develops due to the formation of intense low pressure centre. As it approaches, it spins clockwise in the southern hemisphere and anti-clockwise in the northern hemisphere.

Question 28.
What is a Jet stream ?
Answer:

Jet stream is a thin stream of air generated in the higher reaches of the Troposphere and below the Stratosphere at about 7.4-14 km. altitude. It blows from west to east. Length of this jet stream can be a few thousand kilometer, but the width is only a few hundred kilometre.

Question 29.
What do you mean by ‘Roaring Forties’?
Answer:
In the southern hemisphere, sea surface is much more compared to land surface. Hence, the westerlies can blow over this zone unhindered and with great speed near the 40° S latitude. The wind blows with so much speed that it makes a roaring sound. Hence, the region is called ‘Roaring Forties’.

Question 30.
What are Anabatic wind?
Answer:
Anabatic winds are also called up-slope winds. In mountainous regions, during the day, when the solar radiation heats the mountain slopes, the adjacent cool air gets heated, lightened and rises upward. These are called Anabatic wind.

Question 31.
What are Katabatic winds ?
Answer:
Katabatic winds are also called down-slope winds. In mountainous regions, during the night, when the slopes cool down due to outgoing solar radiation, the adjacent air also cools, gets heavier and sinks down the slopes into the valleys.

Question 32.
What is Sirocco?
Answer:
It is a very hot dry wind of the Sahara desert. It blows from Sahara to the Mediterranean region. It is known as Khamsin in Egypt, Harmattan in Guinea coast of West Africa and Sirocco in Sicily.

Question 33.
What is Mistral ?
Answer:
Mistral is a strong, cold northernly wind experienced on the shores of the northwest Mediterranean region. It blows along the coasts of Spain and France.

Question 34.
What is Bora?
Answer:
Bora is a cold dry wind that blows along the adriatic coast and in northern Italy during winter.

Question 35.
How many kinds of air pressure are there?
Answer:
There are two kinds of air pressure :
(i) High pressure : When air pressure is higher than 760 mm of mercury or 986 millibar.
(ii) Low pressure : When air pressure is lower than 760 mm of mercury or 986 millibar.

Question 36.
What do you mean by Standard Atmospheric Pressure?
Answer:
The pressure exerted by 76 cm of mercury in a bore tube at 0° C temperature on 45° latitude at sea level is known as Standard Atmospheric Pressure.

Question 37.
What kind of pressure is considered as normal air pressure ?
Answer:
Air pressure lying between 986-1013.25 millibars is considered as normal air pressure.

Question 38.
What happens if the isobars lie very close to each other?
Answer:
The closely lying isobars indicate a steep pressure gradient. Steep pressure gradients initiate strong and speedy winds. It increases the chances of storms and cyclones.

Question 39.
Is the atmospheric pressure at sea level all over the world same?
Answer:
It has been tested that atmospheric pressure at sea level does not rise above 788 mm and does not fall below 760 mm. But atmospheric pressure at sea level all over the world is not absolutely same. It varies due to temperature conditions of adjacent areas.

Question 40.
What is the difference between Trough and Ridge?
Answer:
A huge region of low pressure is known as Trough and a huge region of high pressure is known as Ridge.

Question 41.
What kind of pressure conditions prevail over the earth in January?
Answer:
In January, low pressure prevails over the southern hemisphere and high pressure prevails over the northem hemisphere.

Question 42.
What kind of pressure conditions prevail over the earth in July?
Answer:
In July, high pressure prevails over the southern hemisphere and low pressure prevails over the southern hemisphere.

Question 43.
What is the Normal lapse rate of air pressure ?
Answer:
With every 110 m rise in altitude, the atmospheric pressure decreases by 1 cm or 10 mm of mercury in the Barometer, or by 1.34 millibar. This is the normal lapse rate of air pressure.

Question 44.
What is ‘Knot’?
Answer:
‘Knot’ is the unit of measuring winds speed. Knot means the distance in nautical miles, travelled in one hour.

Question 45.
What is an anti-cyclone?

Air pressure increases with decrease in air temperature. When this condition gets intensified, the isobars lie in circular patterns with a high pressure in the centre and low pressure towards the periphery. Thus, winds start blowing outwards from the centre in clockwise direction in the northern hemisphere and in anti-clockwise direction in the southern hemisphere.

Question 46.
Name two local winds in India.
Answer:
Two local winds in India are Loo and Andhi.

Answer in brief : 3 Marks

Question 1.
Mention the characteristics of air pressure.
Answer:
The characteristics of air pressure are :

1. Air pressure decreases with increase in altitude.
2. Hot air is lighter and exerts less pressure.
3. Cold air is heavier and exerts more pressure.
4. Water vapour makes the concentration of gaseous molecules in the air lighter, and hence exerts less pressure. Thus, dry air exerts more pressure than moist air.
5. Sudden change in pressure conditions result in severe storms.
6. Air exerts pressure on all directions.
7. Air pressure is measured in millibar.

Question 2.
Compare between high pressure and low pressure.
Answer:

High Pressure	Low Pressure
i. When air exerts much pressure, it is called high pressure.	i. When air exerts less pressure, it is called low pressure.
ii. Length of mercury column in the glass tube of the barometer is more than 760 mm or 1013.25 millibar.	ii. Length of mercury column in the glass tube of the barometer is less than 760 mm or 1013.25 millibar.
iii. The high pressure zones of the earth are sub tropical high pressure zones near the Tropics of Cancer and Capricorn, and polar hight pressure zones near the North pole and the South pole.	iii. The low pressure zones of the earth are Equatorial low pressure zone, sub polar low pressure zones near the Arctic and Antarctic circles.

Question 3.
Why do high pressure zones lie near the polar areas?
Answer:
High pressure belts lie around the polar regions because,

1. The sun gives the most inclined rays to this region. Heat is very less, hence the air is very cold and heavy.
2. There is very less water vapour in the air as the rate of evaporation is very low.
3. Some air from the adjacent sub-polar low pressure belts rise and descend towards the poles.

Question 4.
Why is the equatorial region a low pressure belt ?
Answer:
The equatorial region has a low pressure belt because:

1. The sun gives its maximum energy to this region by rays perpendicular to the surface. Hence, heat is maximum. The air gets heated, lightened and rises up.
2. Presence of huge water bodies and much heat leads to high rates of evaporation. The air is filled with water vapour and becomes light.
3. The rotation of the earth tends to deflect air due to coriolis force.
4. Presence of vast forests adds up to water vapour in the air due to transpiration.

Question 5.
What are horse latitudes?
Answer:
The sub-tropical belt of calm lying between 25°-35° N is known as Horse latitudes. In early days when trade was conducted only through the oceans, the ships used to slow down and could not sail through this region due to lack of wind. Then in order to reduce weight and preserve drinking water, the horses being carried in the ships were thrown into the ocean. Thus the region was named horse latitudes.

Question 6.
What do you mean by ‘Shifting of Pressure belts’?
Answer:
The rotation of the earth, angle of incidence of solar rays, presence of land surface or water surface, altitude and the seasonal drift of the sun towards the north and towards the south cause the pressure belt to shift by 5°-10° northwards and southwards respectively. This temporary movement of the pressure belts makes them move for about 5°-10° from their average positions. This phenomena is known as ‘shifting of pressure belts.’

Question 7.
Differentiate between wind system and wind current.
Answer:

Wind system	Wind current
i. Wind moves horizontally parallel to the earth’s surface.	i. Wind moves vertically perpendicular to the earth’s surface.
ii. Occurs due to difference in pressure between two places.	ii. Occurs due to difference in temperature.
iii. Influence on human life is remarkable.	iii. Influence on human life is negligible.

Question 8.
Differentiate between north-eastern trade winds and south-eastern trade winds.
Answer:

North-eastern Trade winds	South-eastern Trade winds
i. Blows between 5°-25° N latitudes.	i. Blows between 5°-25° S latitudes.
ii. The wind blows from the region around the Tropic of Cancer towards the Equator.	ii. The wind blows from the region around the Tropic of Capricorn towards the Equator.
iii. Wind gets deflected towards the right.	iii. Wind gets deflected towards the left.
iv. Wind speed is comparatively low due to presence of more land surface in the northern hemisphere. (about 16 km per hour)	iv. Wind speed is high due to presence of vast oceanic surface and less land surface in the southern hemisphere. (about 22 km per hour)

Question 9.
List the characteristics of Westerlies.
Answer:
The characteristics of Westerlies are :

1. Westerlies bring rainfall to western margins of continents.
2. The continents under the influence of westerlies have temperate grasslands on their eastern sides.
3. Westerlies bring about more rainfall during the winter.
4. In the southern hemisphere, the westerlies blow with great speed due to vast ocean surfaces unhindered by land. Hence, the latitudes are named – Roaring Forties, Furious Fifties and Screaming Sixties.

Question 10.
What is an Anticyclone?

Answer:
Winds generated in a region of high pressure surrounded by low pressure all around is called an Anticyclone. In this system, the winds blow spirally outwards from the centre in clockwise direction in the northern hemisphere and anticlockwise direction in the southern hemisphere. Anticyclones are generally associated with light wind and clear sky. Rainfall is light or in drizzles. They prevail commonly in winter when cold air remains near the ground for many years.

Question 11.
Differentiate between land and sea breezes and monsoon winds.
Answer:

Land and Sea breezes	Monsoon winds
i. Blows near coastal areas.	i. Generates near oceans and blows towards land for a long distance in tropical region.
ii. Land and Sea breeze blows alternately for few hours. Land breeze blows during the night and sea breeze blows during the day.	ii. Blows for a few months in a particular season. During summer the wind blows from sea to land, during winter they blow from land to sea.

Question 12.
Differentiate between cyclones and anti-cyclones.
Answer:

Cyclone	Anti-cyclone
i. Low pressure lies in the centre of a cyclone.	i. High pressure lies in the centre of an anti-cyclone.
ii. Winds blow towards the centre.	ii. Winds blow outwards from the centre.
iii. Winds are warm and move upward.	iii. Winds are cold and move downward.
iv. Winds blow anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere.	iv. Winds blow clockwise in the northerm hemisphere and anti-clockwise in the southern hemisphere.
v. Wind velocity is very high.	v. Wind velocity is low.
vi. Cause storms and rainfall.	vi Usually cause no rainfall.
vii. Exists for a short time, but is destructive.	vii. Exists for a long time but is not destructive.

Question 13.
Compare the atmospheric pressure conditions of January and July.
Answer:

Pressure conditions in January	Pressure conditions in July
i. High pressure lies in northern hemisphere and low pressure lies in southern hemisphere.	i. High pressure lies in southern hemisphere and low pressure lies in northern hemisphere.
ii. The pressure belts shift southwards with the southward movement of the sun.	ii. The pressure belts shift northward with the northward movement of the sun.
iii. During this time the wind blows from land towards the sea in the northern hemisphere.	iii. During this time, the wind blows from land towards the sea in the southern hemisphere.

Question 14.
Discuss the effects of air pressure.
Answer:
The effects of air pressure are –

1. Difference in air pressure of different parts of the earth’s surface is the main cause of wind.
2. Heavy storms and often rainfall occur in regions of very less pressure.
3. Snowfall occurs in high pressure regions.
4. Air pressure influences wind, heat and presence and holding capacity of water vapour by the air.
5. Higher altitudes have low pressure. Hence, mountaineers have to carry oxygen cylinders for breathing.
6. In higher altitudes, due to sudden decrease in atmospheric pressure, bleeding may start from nose, ears, eyes etc.

Question 15.
Discuss the characteristics of winds.
Answer:
The horizontal movement of air along the earth’s surface from a region of high pressure to a region of low pressure is known as wind. The characteristics of winds are –

1. Winds blow from high pressure to low pressure regions.
2. Winds (especially planetary winds) are named according to the directions from where they blow.
3. Wind speed depends on the pressure gradient between two places.
4. Wind direction is marked by a Wind Vane.
5. Wind speed is measured by Anemometer in ‘Knots’.
6. The force of the wind is calculated on the Beufort Scale.

Question 16.
What is ‘Coriolis Force’?
Answer:
‘Coriolis Force’ is generated due to the rotation of the earth. The earth being a sphere, speed of rotation goes on reducing from the equator towards the poles. The moving elements on the earth’s surface (wind, ocean currents) thus cannot flow directly in the north-south direction, and get slightly deflected. This was first discovered by the French physicist and mathematician G.G. Coriolis in 1835. Thus the force that causes deflection of moving bodies on the earth’s surface due to rotation is called the ‘Coriolis Force’. In the northern hemisphere, the winds get deflected towards the right and in the southern hemisphere, the winds get deflected towards the left.

Question 17.
Differentiate between the South-West Westerlies and the North-West Westerlies.
Answer:

South-West Westerlies	North-West Westerlies
i. They blow from the Tropic of Cancer towards the Arctic Circle in the northern hemisphere.	i. They blow from the Tropic of Capricorn towards the Antarctic Circle in the southern hemisphere.
ii. They blow between \(23^{1 / 2}\)° N \(66^{1 / 2}\)°N.	ii. They blow between \(23^{1 / 2}\)°S \(66^{1 / 2}\)°S.
iii. Wind speed is lesser than the NW westerlies.	iii. Wind speed is greater than the SW westerlies.
iv. Horse Latitudes lie within this zone.	iv. Roaring 40s lie within this zone.

Question 18.
Why do westerlies cause more rainfall on the western coasts of the continents?
Answer:
The causes of rainfall on the western coasts of the continents by Westerlies are:
i. Westerlies blow from the west towards the east. Hence, before they enter the continent from the western side, they blow over oceans and collect enough moisture.
ii. The continents under the influence of westerlies have mountains and high lands along the western margins. This helps to stop the moisture laden winds and cause rainfall.

Question 19.
Why do the eastern parts of the continents under the influence of westerlies receive less rainfall ?
Answer:
The eastern parts of the continents under the influence of Westerlies receive less rainfall because –
i. The Westerly winds become more and more dry as they move from west to east over the continents and cannot collect moisture due to lack of water bodies.
ii. They shed maximum water at the western margins of the continents due to collision with highlands and mountains.

Question 20.
Differentiate between Trade winds and Westerlies.
Answer:

Trade winds	Westerlies
i. Blow from the Tropic of Cancer and Capricorn towards the Equator.	i. Blow from the Tropic of Cancer to the Arctic Circle and Tropic of Capricorn to the Antarctic Circle.
ii. Blow from the east towards the west.	ii. Blow from the west towards the east.
iii. Wind speed is 16 km per hour in the northern hemisphere and 22 km per hour in the southern hemisphere.	iii. Wind speed is low in the northern hemisphere due to presence of landmass. Wind speed is high in the southern hemisphere due to presence of oceans.
iv. Helped in sailing of ships in early days.	iv. Cause danger to ships sailing in the southern hemisphere due to great wind speed.
v. Cause rainfall on the eastern side of continents.	v. Cause rainfall on the western side of continents.
vi. Cause uniform rainfall in the equatorial region throughout the year.	vi. Cause more rainfall in the winter compared to the summer.

Question 21.
Differentiate between Sea Breeze and Land Breeze.
Answer:

Sea Breeze	Land Breeze
i. Blows during day time from the sea towards the land.	i. Blows during night from the land towards the sea.
ii. Wind speed is greater than land breeze.	ii. Wind speed is lesser than sea breeze.
iii. Wind speed is greatest during noon.	iii. Wind speed is greatest during early morning.
iv. Winds cover a larger area while blowing.	iv. Winds cover a lesser area while blowing.

Question 22.
What is a Cyclone?
Answer:

If a small area suddenly gets heated up, the air present over that area also get heated, lightened and rise upwards. This creates a low pressure trough in the area compared to the surrounding areas. Thus, winds gush in with great speed from all sides towards the centre of low pressure. This is known as a Cyclone. The cyclonic winds move in circular patterns. They blow in the anti-clockwise direction in the northern hemisphere and clockwise direction in the southern hemisphere.

Answer in details : 5 Marks

Question 1.
Discuss the factors affecting atmosphere pressure.
Answer:
The factors that affect atmospheric pressure are :
i. Temperature : Air pressure is inversely related to temperature. Higher the temperature, lower is the air pressure. As air gets heated, it gets lighter and rises upwards, thus exerts less pressure. Conversely, cold air contracts, becomes heavier and descends, thus exerts more pressure.

ii. Altitude : Atmospheric pressure is inversely related to altitude. The lower layers of the air are denser than upper layers. Moreover, the lower layers are compressed
under the weight of the upper layers of air and exert more pressure. As we go higher up, pressure decreases by 10 mm per 110 m rise in altitude.

iii. Water vapour : Air containing water vapour is lighter than dry air. Thus moist air exerts less pressure than dry air.

iv. Rotation of the earth : Rotation of the earth results in swing of air outwards due to centrifugal force. Thus regions of the earth rotating with the highest speed have low pressure zone.

v. Distribution of land and water : Pressure conditions on land and water on the same latitude are not the same. During summer, the land gets heated more than the water, thus a low pressure region is created on the land. The opposite condition occurs in winter.

Question 2.
Discuss the Pressure belts of the world in brief.
Answer:
The world is divided into seven distinct pressure belts. They are :
(i) The Equatorial low pressure belt
(ii) and (iii) The sub-tropical high pressure belts (North and South)
(iv) and (v) The sub-polar low pressure belts (North and South)
(vi) and (vii) The Polar high pressure belts (North and South)

(i) Equatorial low pressure belt : This belt lies between 5°N and 5°S of the Equator. The earth receives maximum heat here. Hence the air is always hot and light. The air also contains a large amount of water vapour. This light air rises vertically giving, rise to a low pressure belt. The region is generally windless and calm. Hence it is also known as doldrums.

(ii) and (iii) The Sub-tropical high pressure belts : These belts extend between 30°-35° N and S. These high pressure belts are not thermally induced. They result due to rotation of the earth, sinking, settling down and piling of air from the equator and sub-polar regions. The cool descending air gradually becomes warm and its water holding capacity increases. As a result there is no condensation and occurrence of rainfall. This is one of the reasons for occurrence of hot deserts on the western sides of the continents present in this region.

(iv) and (v) The Sub-polar low pressure belts : These belts lie between 60°-65° N and S. Due to earth’s rotation, the surface air spreads outward, causing creation of low pressure. The belt is more developed in the southern hemisphere compared to the northern hemisphere because of the presence and dominance of water (oceans) in the southern hemisphere in this belt.

(vi) and (vii) the Polar high pressure belts : These belts lie around the poles in both the hemispheres. These regions have permanent ice caps. Due to immense cold and minimum speed of rotation, the air which is cold and dense, descends near the poles, creating high pressure.

Question 3.
Discuss the causes of wind movement over the earth’s surface.
Answer:
The different causes for wind movement over the earth’s surface are –
i. Difference in temperature : If a place gets heated, the air lying above it also gets heated and lightened and rises up creating a partial vacuum. Thus air rushes from adjacent cooler airs to fill up the vacuum.
ii. Difference in pressure : Difference in temperature between two places cause difference in pressure. Thus winds blow from high pressure to low pressure regions.
iii. Rotation of the earth : While blowing from high pressure to low pressure regions, winds get deflected due to the rotation of the earth.
iv. Nature of landforms : High mountains or plateaus provide obstruction to the wind, hence speed is less. But vaccant and flat places like deserts, plains, etc. experience very speedy winds.
v. Presence of land or water surface: Winds blowing over land surface experience more friction than winds blowing over water surface. Hence wind blowing over land have less speed than wind blowing over water.

Question 4.
Discuss the charateristics of Planetary wind in brief.
Answer:
There are three types of planetary wind:

1. The Trade winds
2. The Westerlies
3. The Polar winds.

i. The Trade winds : Winds that blow from the Sub-tropical high pressure belts to the Equatorial low pressure belts are called Trade winds. According to Ferrel’s

law, due to Coriolis force, caused by earth’s rotation winds deflect to the right in the northern hemisphere and to the left in the southern hemisphere. Hence, the winds are called north-east trade winds in the northern hemisphere and the south-east trade winds in the southern hemisphere. Velocity of NE trade winds is around 16 km per hour and that of SE trade winds is 22 km per hour (due to less landforms and vast oceans).

ii. The Westerlies : The winds blowing from the sub-tropical high pressure belts to the sub-polar low pressure belts are called Westerlies. As the direction of the Westerlies is opposite to that of trade winds, they are also called Anti-trade winds. In the northern hemisphere they blow from the south-west and in the southern hemisphere they blow from the North-West.

iii. The polar winds : The chilled winds blowing from the polar regions to the subpolar low pressure regions are called the polar winds. Since their direction is similar to that of Trade winds, they are also called Polar Easterlies or Polar Trade winds. In this region, the deflection of winds is so high that they appear to blow almost from the east.

Question 5.
What is the ‘Jet Stream’? Discuss its relation with the monsoon winds.
Answer:

Jet stream is a thin stream of air generated in the higher reaches of the Troposphere and below the Stratosphere at about 7.5-14 km. altitude. It blows from west to east. The jet stream can be a few thousand kilometer but width is only a few hundred kilometer.

Relation between Jet stream and Monsoon winds : The westerly Jet stream causes high pressure on the Indian subcontinent in winter. Hence the summer, the Tibet plateau gets excessively heated and drives the subtropical westerly Jet stream north of the Himalaya. The tropical easterly jet stream blows through the centre of the Indian sub-continent, causing low pressure conditions. This gradually attracts the monsoon winds. The onset of monsoon depends on the shifting of the sub-tropical westerly jet stream northwards, which allows the easterly jet to set in. A sudden shift of the westerly jet stream may cause a huge ‘Monsoon burst’.

Question 6.
Differentiate between cyclones and anti-cyclones.
Answer:

Question 7.
Describe some local winds of the earth.
Answer :
i. Sirocco or Khamsin : It is a very hot dry wind of the Sahara desert. It blows from Sahara to the Mediterranean region. It is known as Khamsin in Egypt, Harmattan in Guinea coast of West Africa and Sirocco in Sicily.
ii. Mistral : It is a strong, cold northernly wind experienced on the shores of the North-West Mediterranean region. It blows along the coasts of Spain and France.
iii Bora : It is a cold and dry wind that blows along the Adriatic coast and in northern Italy during winter.
iv. Fohn : It is a warm dry wind blowing down the northern slope of the Alps. Initially it rises as a moist wind from the Mediterranean sea.
v. Chinook : It is a warm, dry, gusty wind blowing down the Rocky mountains by the eastern slopes into the western Prairies.
vi. Loo : It is a strong, dry, hot summer afternoon wind blowing over-North Western India and Pakistan, especially in May and June.
vii. Others : Pampero, Blizzard, Santa Ana, Norwesters etc.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 2.3 Heat, Temperature and Global Warming offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 2.3 Question Answer – Heat, Temperature and Global Warming

Answer in short : 2 Marks

Question 1.
What is ‘insolation’?
Answer:
According to H.C. Gitchfield, radiant energy from the sun that strikes the earth is called insolation. Insolation is received in the form of shortwaves. The amount of insolation that comes to the earth’s surface is only one part of two hundred crore parts of the sun’s heat.

Question 2.
What is albedo?
Answer:
A very little fraction of the sun’s energy comes to the earth as insolation, of which the total energy is not absorbed by the earth. 34% of the insolation is reflected back to space by the dust, ice crystals and cloud present in the atmosphere. This is called ‘albedo’.

Question 3.
What is heat budget?
Answer:
The incoming solar radiation is balanced by an equal amount of outgoing radiation returned from the earth. This balance maintained between the insolation and outgoing radiation is called the ‘heat budget of the earth.’

Question 4.
How is the heat balance of the earth maintained ?
Answer:
The average temperature of the earth remains same more or less throughout the year. The 66% of insolation received during day time is radiated back during the night. Thus, although there may be some seasonal variations, total balance of heat throughout the year is never disturbed. This is how the heat balance of the earth is maintained.

Question 5.
What is the ‘normal lapse rate of temperature’?
Answer:
In the troposphere, the temperature of the atmosphere is inversely proportional to the altitude of a place. With every 1 km or 1000 m rise in altitude, temperature reduces by 6.4°C. This is known as the ‘normal lapse rate of temperature’.

Question 6.
On what factors does the amount of insolation depend?
Answer:
The insolation depends on several factors like – (a) length of day (b) distance between the sun and the earth (c) clarity of the atmosphere (d) angle of incidence of solar rays etc.

Question 7.
What do you mean by ‘inversion of temperature’?
Answer:
By the normal lapse rate, temperature reduces by 6.4°C with every 1 km rise in altitude. But in some cases, it is seen that temperature increases with increase in height. This phenomenon is known as the inversion of temperature. This is common in valleys of mountainous regions during early morning and late nights.

Question 8.
What do you mean by the ‘diurnal range of temperature’ ?
Answer:
The range of temperature between the maximum and minimum temperatures recorded in a single day is called the diurnal range of temperature.

Question 9.
What do you mean by Average or Mean temperature ?
Answer:
The average between the highest and lowest temperatures recorded in a day is called the average or mean temperature.

Question 10.
What is ‘Mean monthly temperature’ ?
Answer:
The average of the mean temperatures of all the days of a month is known as the mean monthly temperature.

Question 11.
What do you mean by the annual range of temperature?
Answer:
Annual range of temperature is the difference between the mean temperatures of the hottest and coldest months of the year.

Question 12.
What is average annual temperature?
Answer:
The average of the mean temperatures of all the months of the year is known as the average annual temperature.

Question 13.
What do you mean by Katabatic winds?
Answer:

Cold air in steep and deep valleys descends down and accumulates at the bottom due to gravity during the night. Such winds by which the cold air is forced to lie below the warm air is called Katabatic winds.

Question 14.
What do you mean by Anabatic winds?
Answer:

Cold air descends into valley bottoms during the night due to Katabatic winds. During day time, this air is gradually heated and warmed. This warm air starts rising along the valley walls. This is known as Anabatic winds.

Question 15.
Name the different temperature zones of the world.
Answer:
The different temperature zones of the world are :

1. The Torrid zone.
2. The North Temperature zone.
3. The South Temperate zone.
4. The North Frigid zone.
5. The South Frigid zone.

Question 16.
What do you mean by temperature zones or belts ?
Answer:

Temperature of the earth’s atmosphere tends to change significantly along with change in latitudes from the equator towards the poles. The earth being round, these latitudinal zones having similar temperature conditions can be demarcated as spherical belts or zones. These are known as temperature zones.

Question 17.
What is a isotherm ?
Answer:
Isotherms are imaginary lines drawn on a map joining places of the same average temperature for a specified period, supposing the places to be reduced to the sea level.

Question 18.
What is global warming ?
Answer:
Global warming is the process of gradual increase of the general temperature of the earth due to increase in the use of green house gases and many other reasons. Temperature of the earth has increased by 1° from 1900 to 2000 .

Question 19.
Name some green house gases.
Answer:
Some green house gases are : Carbon dioxide (C₂), Carbon monoxide (CO), Methane (CH₄), Nitrous Oxide (N₂O), Chloro fluoro carbon (CFC), Water vapour (H₂O), Ozone (O₃) etc.

Question 20.
What is El Nino?
Answer:
El Nino refers to the large scale ocean-atmospheric climatic interaction linked to a periodic warming in sea surface temperatures across the central and eastcentral equatorial Pacific Ocean. The effects of El Nino disturbs the global distribution of rainfall and temperature and also affect the seasons.

Question 21.
What is Solar constant?
Answer:
The rate at which energy reaches the earth’s surface from the Sun through perpendicular rays, usually taken to be 1388 watts per sq. meter is called solar constant.

Question 22.
What is the heat equator?
Answer:
Heat equator or thermal equator is a imagenary belt encircling the earth connects all places having highest mean annual temparature at each longitude around the globe. This line roughly followed the 5° North latitude.

Question 23.
What is Six’s maximum and minimum thermometer?
Answer:
It is a instrument measuring the temperature of the day in terms of maximum and minimum value. So that it helps to calculate the average temparature and the diurnal range of temperature.

Question 24.
What is effective solar radiation?
Answer:
The earth receives one part of two hundred crore parts of sun’s radiation. Of this, about 34% of the heat energy is reflected back to space as Albedo. The remaining 66% of the heat energy that heats up the earth’s surface directly or indirectly is called Effective Solar Radiation.

Question 25.
Why does the atmosphere get heated maximum at 2 pm. even though the vertical solar rays reach the earth’s surface at 12 noon?
Answer: The most important process of heating the atmosphere is radiation by the earth’s surface. Although the earth receives maximum heat through the vertical rays of the sun at around 12 noon, the rate of radiation is maximum at 2 p.m. Hence, the atmosphere gets heated to its maximum during this time.

Question 26.
Name the hottest and coldest places of the earth.
Answer:
The hottest place of the earth is Al Azizia of Libya in Africa (58°C). The coldest place is Vostok of Antarctica (-88°C).

Question 27.
When does a place experience the highest and lowest temperatures in a day?
Answer:
In a day, the highest temperature is experienced around 2 p.m. and the lowest temperature is experienced just before sunrise.

Question 28.
What do you mean by Torrid Zone?
Answer:
The zone spreading from \(23^{1 / 2}\)°N (Tropic of Cancer) to \(23^{1 / 2}\)° S (Tropic of Capricorn is known as the Torrid Zone. It is the hottest zone of the world.

Question 29.
What do you mean by the Temperate Zone?
Answer:
The zone lying between the Tropic of Cancer (\(23^{1 / 2}\)° N) and Arctic Circle (\(66^{1 / 2}\)° N) in the northern hemisphere and the zone between the Tropic of Capricorn (\(23^{1 / 2}\)° O) and Antarctic Circle (\(66^{1 / 2}\)° S) in the southern hemisphere are known as the Temperate Zones.

Question 30.
What do you mean by the Frigid Zone?
Answer:
The zone lying between the Arctic Circle (\(66^{1 / 2}\)° N) and the North Pole (90^{\circ N) in the northern hemisphere and the zone between the Antarctic Circle (\(66^{1 / 2}\)° S) and the South Pole (90° S) in the southem hemisphere are called Frigid zones.

Question 31.
What do you mean by Green House effect?
Answer:
The increasing concentration of green house gases in the atmosphere like Carbon dioxide, Methane, Chloro fluoro carbon, water vapour, ozone etc. are increasing the general temperature of the atmosphere by absorbing and holding back more and more heat. This gradual process of increasing the atmospheric temperature in general is called global warming, which is the outcome of Green House effect.

Answer in brief : 3 Marks

Question 1.
Differentiate between heat and temperature of the atmosphere.
Answer:

Heat	Temperature
i. Heat is an energy.	i. Temperature is the measure of the condition of heat of any object.
ii. Heat leads to change of temperature.	ii. Temperature is the result of heat.
iii. Two objects having same temperature may have different heat contents.	iii. Two objects having same heat content may have different temperatures.
iv. Measured in calories or joules with the help of calorimeter.	iv. Measured in degree centigrade or fahrenheit with the help of thermometers.

Question 2.
Why does temperature decrease with increase in altitude?
Answer:

Atmospheric temperature decreases with increase in altitude for the following reasons :

1. Insolation first heats up the earth’s surface. This heat is radiated into the atmosphere gradually heating the layers from bottom to top.
2. The upper layers of the atmosphere are less dense and can rapidly radiate out heat and get cooled.
3. Pressure is less in the upper levels of the air, hence their heat absorbing capacity is also less.
4. The dust and other particles present in the upper layers absorb most of the heat and hence the air remains cool.

Question 3.
Why is lowest temperature recorded during dawn or early morning ?
Answer:
The earth takes almost the whole night to radiate back the insolation that it receives during the day time. Hence it becomes coolest during the early morning or dawn, before the insolation of the next day starts.

Question 4.
What are the importances of temperature in the atmosphere?
Answer:
The importances of temperature in the atmosphere are:

1. Temperature helps in birth, growth and other activities of living things on the earth.
2. It helps in germination of seeds.
3. Difference in temperature in different regions of the earth brings about growth of different species of plants and animals in different regions of the world.
4. Rate of evaporation, formation of clouds, rainfall, snowfall etc. depend on temperature conditions of a place.
5. Difference in temperature of different places leads to difference in air pressure, hence leads to generation of winds.

Question 5.
Why is annual range of temperature of deserts very high?
Answer:
The reasons for great difference of temperature between hottest and coldest months in deserts are as follows :
(i) Deserts are composed of sand particles containing quartz which absorb and release heat very quickly. Hence extremes of temperature are seen.
(ii) Lack of vegetation in deserts attract very less rainfall. Hence extreme temperatures are seen.
(iii) The sandy soil of deserts have very less water holding capacity. Hence the soil gets heated very quickly and also release heat very quickly.

Question 6.
Explain the process of radiation in heating the earth’s atmosphere.
Answer:
The insolation received by the earth comes in the form of short wave radiations and reach the earth’s surface without heating the atmosphere much. When this heat is radiated back by the earth in the form of long waves, it is easily absorbed by the air surrounding it. This terrestrial radiation helps to heat up the atmosphere to the maximum.

Question 7.
What is the role of conduction in heating the atmosphere ?
Answer:
Conduction is the process in which one particle transmits heat to another particle. Air is a poor conductor of heat and only the lower layers of the atmosphere are heated by conduction. Thus, it is a less significant process of heating the atmosphere.

Question 8.
What is Convection?
Answer:
Transfer of heat by the movement of a mass or substance from one place to another is called convection. The air particles being heated from their contact with the earth’s surface become lighter and rise. The comparatively cool air particles in the upper layers are heavier and come down slowly. This process form air currents that are known as convection currents.

Question 9.
What is Advection?
Answer:
Advection is the process by which the hot air moves along the earth’s surface horizontally and heats up the cool air of some other place. By this process, the heat of the lower latitudes is transmitted towards the higher latitudes. This process may affect temperatures of adjacent local areas as well. Eg. – ‘Loo’ is transmitted by the process of advection.

Question 10.
What are the effects of El Nino?
Answer:
The effects of El Nino are :

1. Occurrence of El Nino considerably reduces rainfall in the south-east Asian countries, Indonesia, Australia and regions near the Indian ocean.
2. Rainfall occurs in Peru and Atacama desert region of South America.
3. Warm ocean curents influenced by the El Nino warm up the waters near the coastal region of Peru. Thus planktons cannot survive. This harms fish accumulation and fish catch.
4. It obstructs the blowing of monsoon winds, thus reducing rainfall.
5. It causes the weather of the western hemisphere to become warmer than normal.
6. The corals and other sea creatures may get killed.

Question 11.
What are the effects of La Nina ?
Answer:
The effects of La Nina are :

1. La Nina causes heavy rainfall in western part of Pacific ocean, south and eastern Asia and north and eastern Australia.
2. In the southern hemisphere, the months from December to February remain much moist and the equatorial region in Africa remains comparatively drier.
3. Tropical cyclones increase in South and Eastern Asia.
4. Severe droughts persist in Peru and adjacent areas in South America.
5. North-western parts of North America receive more rainfall than normal.
6.  Canada experiences severe cold winters.

Question 12.
Why is lowest temperature experienced during very early morning or just before dawn?
Answer:
The earth receives insolation throughout the day and radiates it back after sunset. It takes almost the whole night to radiate back all the heat before it starts receiving heat once again the next day. Hence, the atmosphere remains coolest during the dawn and very early morning, and the lowest temperatures are recorded during this time.

Question 13.
What are isotherms ? What are its characteristics?
Answer:
Isotherms are imaginary lines drawn on weather maps to join places having the same temperature at the same time. The characteristics of isotherms are:

1. The isotherms run almost parallel to the latitudes.
2. They run almost straight and parallel over the oceans, but there may be deviations and ups and downs when they run over the landmasses due to variations in climatic conditions over land.
3. Value of the isotherm goes on reducing from the equatorial to polar regions.
4. Lack of cloud cover allows insolation and radiation unhindered.

Question 14.
Why are cloudless nights cooler than the cloudy nights ?
Answer:
Cloud directly absorb 48% of sunlight in daytime which affect the insolation of the earth. Similarly when temperature of the earth is radiate in night time to balance the temperature on the surface of the earth, cloud prevents to radiate temperature. So that when the nights have cloud covered sky, these are warmer than the nights have clear sky or cloudless sky.

Question 15.
What do you mean by inversion of temperature?
Answer:
Generally temperature decreases with increasing height of the surface at a rate of 6.4°C per 1000 m. But in some exceptional cases, temperature is increase with increasing height of the surface. This phenomena is called inversion of temperature. In mountaineous regions, at night, there has been blown cold Katabetic wind from hill top to valley. As a result temperature on the hill top area are warmer than valley region.

Question 16.
Why the places of lower altitudes are warmer than the higher altitudes?
Answer:
Air density decreases with increasing height. In addition to this, amount of water vapour and dust particles are also decrease in higher altitudes. For these reasons, air is more warmer in low lying area and cooler in high.

Answer in details : 5 Marks

Question 1.
Explain the causes of difference in temperature in the atmosphere.
Answer:
The factors that cause difference in temperature in the atmosphere are :
(i) Latitude : The latitudes exercise the most dominant control over the duration of sunshine and thereby the length of the day. The higher is the latitude, the lower is the amount of heat received.

(ii) Altitude : By the normal lapse rate, temperature decreases by 6.4°C with every 1 km rise in altitude. Hence, higher altitude places are colder than lower regions.
(iii) Distribution of land and water bodies : Heat absorbing capacities of land and water bodies are not equal. Latent heat capacity of water is more compared to land. Hence, extremes of temperature are noticed on land, while water bodies show moderate range of temperature.
(iv) Wind : Hot winds blowing over cold areas tend to increase atmospheric temperature and vice versa.
(v) Ocean currents : Planetary winds influence ocean currents. Warm currents may be directed towards cold regions, thus increasing the temperature of the coastal regions, and vice versa.
(vi) Slope of land : In mountainous regions, one side receives more sunlight than the other. Hence, the slope that receives more sunlight is warmer than the opposite slope which is comparatively cooler.

(vii) Cloud cover : Cloud cover acts like an umbrella preventing escape of heat from the atmosphere, thus increasing temperature. Clear sky allows insolation and radiation at greater rates, thus resulting in large temperature differences between day and night.

(viii) Rainfall : Rainfall helps to reduce heat. Hence, heavy rainfall areas near the equator may appear to be less warm compared to less rainfall areas of tropical regions.
(ix) Vegetation : Dense vegetative cover stops solar energy to heat up the ground and also attract rainfall, hence influences the temperature conditions.
(x) Soil : Soils that can hold water, control temperature conditions as they do not get heated very fast. Dry and coarse soils get heated and cooled very fast.
(xi) Industrial and urban growth : Increase in number of industries, cars, cities and several urban activities tend to heat up the atmosphere more than rural areas.

Question 2.
Describe the temperature belts/zones of the earth in brief.
Answer:

The earth is divided into several temperature belts or zones according to the latitudes. They are : Torrid zone, North and South Temperate zones and North and South Frigid zone.

(i) Torrid zone: This lies from the Equator (0°) to the Tropic of Cancer (\(23^{1 / 2}\)° N) in the north and Tropic of Capricorn (\(23^{1 / 2}\)° S) in the south. The characteristics are:
(a) The sun gives vertical rays to this region.
(b) Length of day and night remains almost equal throughout the year.
(c) Average temperature is quite high (about 27°C )

(ii) North and South Temperate Zones : These zones spread from the Tropic of Cancer (\(23^{1 / 2}\)° N) to the Arctic Circle (\(66^{1 / 2}\)° N) in the north and from Tropic of Capricorn (\(23^{1 / 2}\)° S) to the Antarctic circle (\(66^{1 / 2}\)° S) in the south. The characteristics are :
(a) Sun gives medium inclined rays to this region.
(b) Average temperature is cooler than the Torrid zone.
(c) The \(23^{1 / 2}\)°-50° region is known as the warm temperate zone while the 50°-\(66^{1 / 2}\)° zone is known as the cool temperate zone.

(iii) North and South Frigid Zones : These zones spread from the Arctic Circle (\(66^{1 / 2}\) ° N) to the North Pole (90° N) in the north and from the Antarctic Circle .(\(66^{1 / 2}\)° S) to the South Pole (90° S) in the south. The characteristics are :
(a) The sun gives highly inclined rays to this region.
(b) Length of day and night is highly inequal.
(c) Average temperature remains below 0°C.
(d) Most of the time the region experiences snowfall and remains snow-covered.

Question 3.
What are the effects of global warming ?
Answer:
The effects of global warming are discussed below :
i. Melting of glaciers : Global warming increases the average temperature of the earth’s atmosphere, which results in melting of ice caps and glaciers. This will submerge coastal areas due to increase in level of sea water. The fluvial cycles will be disturbed and landforms will change. Many flora and fauna may be destroyed.

ii. Climatic change : The northern hemisphere will become hotter than the southern hemisphere due to presence of more land masses here. Amount of rainfall in Tropical regions will increase by 10-15%. The northern countries may experience flood and the southern countries will experience drought in the northern hemisphere.
Summers will be longer. Chances of thunder storms and cyclones will increase.

iii. Ecosystem : Change in climate due to global warming may result in extinction of many species of birds, animals and plants.

iv. Effect on vegetation and agriculture : Excessive heat may hamper the growth of coniferous trees in hilly areas. Mangroves may be drowned due to rise in sea water level. Some crops like corn, sugarcane, jowar, bajra etc. will have increased production while crops like rice, wheat, barley, soyabean, tobacco, jute etc. will reduce their growth.

v. Spread of diseases: The germs and bacteria will become highly active and spread diseases like dengue, malaria, yellow fever, encephalitis etc. Some tropical diseases may spread to higher latitudes also.

vi. Spread of deserts : High temperature and high rates of evaporation will turn many places arid and hence boost the spread of deserts.

vii. Forest fires : Too much heat will dry up leaves and branches and cause frequent forest fires.

Question 4.
What do you mean by green house gases? What are the uses of green house gases?
Answer:
The gases which play an important role in increasing the average temperature of the earth’s atmosphere are called Green House Gases. Some of the Green House Gases are Carbon Dioxide (CO₂), Carbon Monoxide (CO), Methane (CH₄), Chloro fluoro carbon (CFC), Nitrous Oxide (N₂O), Water vapour, etc. Uses – The Green House Gases are prepared naturally in the environment and are also sometimes the outcome of human activities. These gases are very important for life activities. The sun’s energy reaches the earth’s surface daily as insolation, and is radiated back daily. The Green House Gases trap the outgoing infrared radiation and send it back towards the earth’s surface. This helps to keep the earth’s atmosphere warm, which would have otherwise become so chilled due to out-radiation that no life would have been possible on earth. But the problem is, if the amount of Green House Gases increases drastically, they will hold back so much heat that it will increase the atmospheric temperature at alarming rates. This condition will also be not suitable for existence of life on earth.

Practicing with West Bengal Board Class 10 Geography Book Solutions and West Bengal Board Class 10 Geography Question Paper 2019 alongside detailed explanations can lead to a deeper understanding of the subject.

WBBSE Class 10 Geography Question Paper 2019

Group-A

1. Write the correct answer from the given alternatives

1. The process by which the height of the earth’s surface increases is ………….
Answer: Aggradation.

2. Deep cracks on the surface of the mountain glacier are called ………….
Answer: Crevasse.

3. Annual range of temperature remains minimum in ………….
Answer: Equatorial climate region.

4. Cold local wind that blows in Rhone valley of France is called ………….
Answer: Mistral

5. The place where warm and cold ocean currents converge is called ………….
Answer: Cold wall.

6. When the distance between the earth and the moon is farthest, it is called-
Answer: Apogee.

7. In human body, contaminated water may cause ………….
Answer: Diarrhoea.

8. The main basis of state recognisation in India is ………….
Answer: Language.

9. The source of river Ganga is ………….
Answer: Gangotri glacier.

10. In India, the largest multipurpose river valley project is ………….
Answer: Bhakra-Nangal.

11. The state which ranks first in production of rice per hectare is ………….
Answer: West Bengal.

12. The required raw materials of iron and steel industry include.
Answer: All of them.

13. According to 2011 census the number of metropolis in india is ………….
Answer: 53

14. The latitudinal and longitudinal extension of million sheet topographical map is ………….
Answer: 4°x4°

Group-B.

1. If the statement is true, write ‘T’ and if false, write ‘F’ against the following :

1. Altitude of snowline varies with latitudes.
Answer: True

2. Wind velocity is measured with the help of Anemometer.
Answer: True

3. Salinity of sea-water is maximum in Equatorial region.
Answer: False

4. The highest plateau of India is Deccan Trap.
Answer: False

5. The old alluvial soil of Ganga plain is called Bhangar.
Answer: True

6. Vishakhapattanam is the only tax-free port of India.
Answer: False

7. Red coloured lines are used to show roads in satellite images.
Answer: False

2. Fill in the blanks with suitable words

1. Holes formed by abrasion on river bed are called pot holes.
2. Smog is formed by mixing of dust and fog during winter in industrial region.
3. Labrador current causes snowfall in New Foundland.
4. Waste paper is a solid/biodegradable type of wastes.
5. Tropical early jetstream forests south-west monsoon winds to blow over India.
6. The southernmost most paint of mainland India is kanyakumari.
7. Kolkata is the most populous city of India.

3. Answer in one or two words

1. Which type of rainfall is found in Temperate zone?
Answer: Frontal or cyclonic rainfall.

2. Which island of Sundarban was completely submerged due to global warming?
Answer: New Moore island.

3. Which type of natural vegetation is found in the desert region of India?
Answer: Xerophytes.

4. On which quarters of moon, does Neaptide occur?
Answer: 1st and 3rd quarters of the moon.

5. In which part of the course, river Ganga is maximum polluted?
Answer: Middle course.

6. Name one Zaid crop of India.
Answer: Aus rice, nuts, pumpkin, cucumber, etc.

7. Which state of India leads in ‘Rain-water harvesting’?
Answer: Tamil Nadu.

8. Where is the headuarter of ‘Survey of India’ located?
Answer: Dehradun.

4. Match the left column with the right column.

1. Prominence of ozone gas	a. Gurgaon
2. Research Institute of sugarcane	b. Jammu & Kashmir
3. Largest automobile manufacturing industrial centre	c. Stratosphere
4. Karewa	d. Lucknow

Answer:
1- c, 2-d, 3-a, 4-b

Group-C

3. Answer the following in brief

Question 1.
What is denudation?
Answer:
After weathring, when the weathered earth materials are remained from their position by erosion and mass wasting, the surface beneath the debris becomes open and forms a new landform. This process of opening up of the new surface of the landform is called denudation.
Denudation-Weathering + Erosion + Mass wasting

OR.

What is inversion of temperature?
Answer:
By the normal lapse rate, temperature reduces by 6.4°C with every 1km or 1000m rise in altitude. But in some cases, it is seen that temperature increases with increase in height or altitude. This phenomenon is known as the inversion of temperature. This is common in valleys of mountainous regions during early morning and late night

Question 2.
What is ‘Inter-tropical convergence zone’?
Answer:
The Inter-tropical convergence zone is the region around the equator, extending up to about 5°-10° N and S latitudes. It is called so because the Northeastern and South-eastern Trade winds meet in this region.

OR.

State the definition of ocean current.
Answer:
A continuous and regular horizontal movement of ocean water in a fairly defined direction over a great distance on the surface or sub-surface of the ocean is called ocean currents. they are mostly caused by wind direction, rotation of the earth, temperature, salinity and density of ocean water, prsence and location of landmass, etc. Ocean currents are of two types-warm currents and cold currents.

Question 3.
Define waste management.
Answer:
Waste management is the method of collecting wastes scientifically, segregating then, taking steps for recycle, reuse and reduction, so that the ultimate damage or pollution caused by the wastes comes down to the minimum.

OR

What do you mean by radioactive wastes?
Answer:
Radioactive wastes are by-products of various nuclear technology processes. Industries generating radioactive wastes include nuclear medicine, nuclear research, nuclear power, manufacturing, construction, coal and rare-earth mining, nuclear weapons reprocessing, etc, Radioactive wastes include any material that is either intrinsically radioactive or that has been contaminated by radioactivity.

Question 4.
Where is Malnad region located?
Answer:
The Malnad region is located in the western part of the Karnataka plateau. This region is 320km long and 35km wide. It is highly dissected, and have deeply cut valleys.

OR.

Name two watershed regions of India.
Answer:
The main watershed regions of India are :

• The Himalaya and the Karakoram ranges.
• The Vindhya-Satpura ranges.
• The Western Ghats.

Question 5.
What do you mean by millet crops?
Answer:
Millets are a group of highly variable small-seeded grasses, widely grown in India as well as around the world as foodgrains for man and fodder for animals. The millets are hardy grains that can grow well in dry zones as rain-fed crops, under conditions of low soil fertility and low soil moisture. Eg- Jowar, Bajra, Ragi, etc.

OR.

Name one agro-based and one forest-based industries of India.
Answer:

• Agro-based industries in India: Sugar mills, rice mills, cotton textile industry, edible oil mills, tea industry, coffee industry.
• Forest-based industries in India: Paper industry, match box and card board industry, rubber industry, furniture industry.

Question 6.
State the definition of satellite imageries.
Answer:
Satellite imageries are photographs of the earth and other planets captured by imaging satellites that are installed in space. These are prepared by reading and representing the signals sent by the satellites with the help of high technological know-how.

OR.

State the use of Representative Fraction (R.F.)
Answer:
Representative Fraction (R.F) is a scale which is represented as a fraction that contains no unit. Hence, it can be used for any unit eg. cm to m or km, inch to feet, etc. It is readable and usable in any country with a unit system suitable to them.

Group-D

4. Give brief explanatory answers

Question 1.
State three differences between ‘Seif dunes’ and ‘Barkhans’
Answer:
Seif dunes

• The term Seif comes from the Arabian word ‘Seif’ meaning a straight sword.
• Formed like straight lines parallel to the wind direction
• They are narrow and straight and look like parallel ridges.
• They are very long dunes, Width is very less, but height may be a few be hundred metres.

Barkhans

• The term Barkhan comes from the Turkish word ‘Barkhan’ meaning sand mountain.
• Formed like a curve diagonal or perpendicular to wind direction.
• They are crescent-shaped dunes. The windward side is convex and the beward side is concave.
• They are not very huge in size. Widthh lies between 20-30m and height may around 30m.

OR.

Briefly explain any three factors to identify the mediterranean climate in Temperature-Rainfall graph.
Answer:
The Mediterranean climate can be identified with the help of the following factors :

• Average annual temperature remains about 13°- 18°c
• Average summer temperature is 14°-22°c
• Average winter temperature is 10°-14°c
• Average annual rainfall is 35-75cm, which mostly occurs during winter due to the moist westerly winds.

Question 2.
Briefly discuss any three effects of wastes on environment.
Answer:
The effects of wastes on the environment are :

• Solid wastes lying on the ground for a long time pollute the soil and water of the region. It may spread bad smell and cause air-pollution as well.
• Chemical wastes coming from pesticides, insecticides, etc. Tend to reduce nitrogen content of the soil and reduce fertility. Numerous animals and microorganisms may get killed, and land may gradualy become unproductive.
• Accumulation of wastes in rivers, lakes, ponds, oceans, etc. cause death of numerous aquatic plants and animals. Fishes may loose their reproductive capacity. Water ecosystems may get disrupted.
• Wastes disposed on grounds change the chemical properties of soils. Soils may become acidic and salty and unfit for vegetation growth.

OR.

Briefly discuss the role of students in waste management from any three perspectives.
Answer:
Effective waste management is best achieved at household level, and students can take an active role in this process. They can take up the following steps-

i. Reduce waste creation :

• Use towels and ceramic plates instead of paper napkins and disoposable plates.
• Use biodegradable shopping bags instead of plastic bags.

ii. Reuse things :

• Use old clothes, old toys, books, etc. from elders.
• Make innovative items from discarded things Eg- Penstand from soda cans, Rags from old clothes.

iii. Cleaning programmes :

• Awareness camps and demonstration programms regarding garbage disposal.
• Schools can arrange groups of students for regular survey, Whether the local people are following cleaning and garbage disposal systems or not.

Question 3.
Mention three differences about characteristic features of tropical evergreen and tropical deciduous vegetation of India.
Answer:

Tropical Evergreen forests	Tropical deciduous forest
i. Tropical evergreen forests are very dense.	i. Tropical deciduous forests are compartively less dense.
ii. The trees are very tall and highly branched.	ii. The trees are moderately tall and branched.
iii. The trees do not shed their leaves altogether in one season. Thus the forest appears green throughout the year.	iii. The trees shed their leaves together in the dry season, hence the name deciduous.
iv. The leaves of the trees create a canopy over the head of the forest and allow very little sunlight to penetrate the forest.	iv. The leaves of the trees are comparatively smaller in size, hence do not create a canopy over the head of the forest. Hence, the forests receives sufficient sunlight.

OR.

Explain with examples the influence of raw materials on the developments of industries in India.
Answer:
Development of industries in any region is dependent upon various factors. Raw materials is one of them.

a. Availability of a certain raw material in a region determines the development of a particular industry in that region. Eg-Availability of coal and iron are along with other necessary raw materials in the Asansol-Durgapur belt has helped in the growth of iron and steel industry in that region.

b. Unless the particular raw material is available in a particular region, the related industry cannot grow, even if all other necessary things are available. Eg-Sugar industry cannot develop in Rajasthan due to unavailability of sugarcane in the vicinity.

c. Nature of raw materials determines the location of the industry. Eg-Sugar mills must be located near the sugarcane producing regions, so that the canes can be moved to the mills very fast. If the raw materials are pure, like cotton industry can be located at the source of raw materials or at the market.

Question 4.
Briefly discuss about three main characteristic features of satellite imageries.
Answer:
The characteristic features of satellite imageries are :

• They can supply complete weather information and imagery of a full hemisphere at a time.
• Imageries can also be obtained in segments for detailed descriptions.
• They help in resource surveys, for eg-locating huge collection of fishes in ocean water, monitoring agricultural yields, etc.
• The informations collected by satellite imageries is digital, that can be easily analysed by computers.

OR.

Mention the merits and demerits of remote sensing.
Answer:
The merits of remote sensing are :

• Remote sensing helps to conduct surveys of regions from very long distances with the help of satellites, without coming in physical contact with the region.
• Surveys can be easily conducted during day or night time and on any kind of terrain.
• Most of the work in remote sensing is done with the help of computers and other sophisticated machines, Hence, very little man-power is required.

The demerits of remote sensing are :

• Remote sensing is a very expensive affair, as it includes use of highly sophisticated computers and machineries and satellite services.
• Remote sensing requires a special kind of training to analyse the images. Hence the images are not readable or usable for common people.
• Sometimes large scale engineering maps cannot be prepared from satellite data which makes remote sensing data collection incomplete.

Group-E.

5. Answer any two questions from the following :

Question 1.
Describe with sketches three major landforms developed by erosional work of rivers.
Answer:
The different landforms developed by the erosional works of rivers are :

i. Gorge or V-shaped valley: In the upper course of the river, the down-cutting force is much more than lateral of side-cutting force of erosion. Hence the channel develops more depth than width, and takes the shape of a V-shaped valley.

ii Canyon or I-shaped valley: When the river flows through an arid region made up of nonresistant rocks, most of its energy is spent in down-cutting rather than widening of the valley. Thus the valley takes the shape of an ‘I’-shaped valley.

iii. Pot holes: Round disc-like depressions curved by the swirling water and rock fragments on the bed or floor of the river are called pot holes.

iv. Waterfalls : When water of the river falls freely from a height due to very steep slope, it is called a waterfall. They are further classified into rapids, cataracts and cascades.

Question 2.
Explain the factors responsible for the formation of equatorial low pressure belt and polar high pressure belts.
Answer:
The factors responsible for the formation of equatorial low pressure belt are:

• The sun gives its maximum heat to this region through perpendicular rays. Hence, air gets heated, lightened and rises up.
• Presence of huge water bodies and much heat leads to high rates of evaporation. The air gets filled with water vapour and becomes light.
• Rotation of the earth tends to deflect air due to coriolis force.
• Presence of vast forests add up to water vapour in the air due to transpiration.

The factors responsible for the formation of polar high pressure belts are :

• The sun gives the most inclined rays to the polar regions. Heat is very less, hence the air is very cold and heavy.
• There is very less water vapour in the air, as the rate of evaporation is very less.
• Some air from the adjacent sub-polar low pressure belts rise and descend towards the poles, and increase the density of air over there.

Question 3.
Give an account of occurance of orographic rainfall with suitable example and diagram.
Answer:
Orographic rainfall is typically found in hilly and mountainous regions. When the moisture lader winds blowing from the sea strike against mountains, the humid winds rise up along the windward slope.

As they rise, they cool down and bring heavy rainfall to the windward slope. Such a rainfall caused due to hindrance or obstruction by a mountain is called orographic or relief rainfall. (‘Oro’-greek word meaning mountain).

Question 4.
Explain the causes responsible for the development of high tides and ebb.
Answer:
The causes responsible for the development of high tides and ebb tides are :
i. Gravitational pull of the moon: Although both the sun and the moon exert gravitational force on the earth the sun’s force is only 46% of that of the moon, due to its large distance from the earth compared to the moon. Hence, the moon’s influence on the tides is twice as strong as that of the sun.

The water of the earth nearest to the moon is pulled by its gravitational force. This makes the water on this side bulge, causing high tide. Waters on the opposite side also experience high tides at a comparatively lower scale. The areas perpendicular to these areas of high tide experience ebbs or low tides.

ii. Effect of centrifugal force for rotation of the earth: Rotation of the earth causes generation of centrifugal force. Which tends to throw the waters outwards. This causes the rise of water as tides. The regions lying perpendicular to the regions of high tides experience ebbs or low tides.

iii. Gravitational pull of the sun: The sun also helps to cause tides. When it lies in the same side as the moon, it causes very big tides. When the sun lies in the opposite direction to the moon, it causes weaker tides.

2. Answer any two questions from the following :

Question 1.
State the differences between the physical characteristics of North and South Indian rivers.
Answer:
The differences between the physical characteristics of the North and South Indian rivers are :

North Indian Rivers	South Indian Rivers
1. The North Indian rivers originate from the Himalayan range. Hence they are both rainfed and snowfed.	1. The South Indian rivers originate from the plateau region. Hence they are only rainfed.
2. The rivers are perennial, as they are both rainfed and snowfed.	2. The rivers tend to dry up in the dry season. Hence, they are non-perennial.
3. Most of the rivers exhibit their upper, middle and lower courses. Hence, they are ideal rivers.	3. Most of the rivers do not exhibit the three courses prominently. Hence, they are not ideal rivers.
4. The rivers are very long. They form ‘V’ and ‘I’-shaped valleys in the upper course.	4. The rivers are not very long. They mostly run through rugged regions and form less deep valleys.
5. The rivers are navigable in the middle and lower courses as the rivers are perennial and these regions have very gentle slope.	5. The rivers are not navigable as they are non perennial, and flow over rugged terrain.
6. These rivers have more number of tributaries.	6. These rivers have less number of tributaries.
7. These rivers carry a huge amount of silt and hence form big deltas at their mouth.	7. These rivers carry comparatively lower amount of silt, and hence form smaller deltas.

Question 2.
Give a brief account of alluvial and black soils of India.
Answer:

Alluvial soil	Black soil
1. Formed by deposition of sand, silt clay and organic matter brought down and deposited by rivers.	1. Formed by weathering of basalt rocks.
2. The colour of the soil varies from lightbrown to dark-grey.	2. The colour of the soil varies from black to dark-brown.
3. Found in the river valleys of India, especially along the middle and lower courses.	3 . Found in the plateau region of Maharashtra, parts of Gujarat and Madhya Pradesh, parts of Andhra Pradesh, Karnataka and Tamil Nadu.
4. Alluvial soil is best for growing crops like rice, wheat, sugarcane, jute, etc.	4. Block soil is best for growing crops like cotton, tobacco, jowar, wheat, etc.

Question 3.
State favourable physical conditions required for cultivation of wheat.
Answer:
The favourable physical conditions required for cultivation of wheat are :

• Temperature: Wheat prefers temperature around 155°c. The temperature should be low at the time of sowing, but as the time of harvesting approaches, higher temperature (about 21°c-26°c) is required for ripening of the crop.
• Rainfall: Wheat thrives well in areas receiving an annual rainfall of about 75cm – 100 cm. In areas receiving rainfall less then 50cm, the deficiency is recovered by irrigation.
• Frost: There should be atleast 100 frost-free days. Long gloomy or foggy weather is harmful for crop.
• Soil: Chernozem is the best suited soil for wheat. It also grows well in light clayey or heavy loamy soil.
• Land: Wheat grows well in well-drained slightly rolling plains

Question 4.
Discuss the importance of transportation system in India.
Answer
The importance of transportation system in India are –

• Transport system helps in moving agricultural products, industrial raw materials, finished manufactured goods, etc to the required regions.
• In helps in transportation of labor and other necessary things for the development of agricultural, industrial and other sectors.
• It makes different products available to all the corners of the country, so that uniform development can be made possible.
• It helps in growth of new towns and bigger cities and hence brings about urbanisation.
• It helps to remove regional disparities and inequalities.
• It makes administrative works easier.
• It helps to raise the National Income and bring about socio-economic development of the country.

Group-F.

Locate the following with appropriate symbols and names on the given outline map of India. Attach the map with the answer script.

1. Vindhya mountain
2. Loktak Lake
3. River Mahanadi
4. One-rainshadow region
5. One mangrove forest region.
6. One desert soil region.
7. One sugarcane producing region of north India.
8. One heavy engineering industrial centre of eastern India.
9. Vishakhapathnam Port.
10. A megacity of western coast.

OR
Answer any ten of the following questions :

1 Name the longest river of South India.
Answer: Godavari.

2 Which is the largest lagoon in the eastern coast of India?
Answer: Chilika lake in Odisha.

3 Name one tributary of Indus that flows through Punjab plain.
Answer: River Sutlej.

4 In which month kalbaisakhi occurs in India?
Answer: April-May.

5 Name a state having laterite soil.
Answer: Karnataka, Kerala, Madhya Pradesh.

6 What type of natural vegetation grows on saline soil of India?
Answer: Mangrove vegetation.

7 Name one plantation crop produced in India.
Answer: Tea, coffee.

8 Where is the largest petro-chemical industry of India located?
Answer: Gujarat.

9 Name the most populous state of India according to 2011 census.
Answer: Uttar Pradesh.

10 What is the name of the international Airport of West Bengal.
Answer: Netaji Subhas Chandra Bose International Airport.

11 What are the dry river vallays of the deserts called?
Answer: Wadis.

12 In which layer of the atmosphere, disturbances are found?
Answer: Troposphere.

13 Name the highest peak of South India.
Answer: Dodabetta Peak.

14 Name and iron and steel industrial centre of West Bengal.
Answer: Kulti, Burnpur, Durgapur.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 2.2 Layers of the Atmosphere offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 2.2 Question Answer – Layers of the Atmosphere

Answer in short : 2 Marks

Question 1.
Name the different layers of the atmosphere.
Answer:
The different layers of the atmosphere are – Troposphere, Stratosphere, Mesosphere, Ionosphere or Thermosphere and Exosphere.

Question 2.
What is the Tropopause?
Answer:
Tropopause is the transition zone between the troposphere and the stratosphere. It extends for about 2-3 km. Here the temperature remains constant.

Question 3.
What is the Stratopause?
Answer:
Stratopause is the transition zone between the stratosphere and the mesosphere. Temperature in this zone remains constant.

Question 4.
What is the mesopause ?
Answer:
Mesopause is the transition zone between the mesosphere and the ionosphere or the thermosphere. Temperature in this zone remains constant.

Question 5.
What is the ozone layer ?
Answer:
There is a layer in the stratosphere at a height of 20-45 km, which has a high concentration of ozone gas. This portion of the stratosphere is called the ozone layer or the ozonosphere.

Question 6.
Describe the exosphere.
Answer:
The exosphere lies above the thermosphere and extends up to 960 km. It gradually merges with the interplanetary space.

Question 7.
What is normal lapse rate?
Answer:
A lapse rate is the rate at which temperature of the atmosphere decreases as the altitude increases in troposphere. Temperature decrease at the rate of 6.4°C per 1000 mt. in the troposphere.

Question 8.
What is the Van Allen radiation belt ?
Answer:
Energetic charged particles mostly originated from solar wind are captured by and held around the planet earth called Van Allen radiation belt. Earth has two such belts.

Question 9.
What do you mean by nacreaous cloud ?
Answer:
One of the polar stratospheric clouds, that consist of only ice crystals are called nacreous cloud. These are not harmful. These are mostly observed during twillight. These are not precipitation cloud.

Answer in briefly : 3 Marks

Question 1.
Describe the Troposphere.
Answer:
The lower-most layer of the atmosphere lying closest to the earth’s surface is called the Troposphere. It extends up to 18 km at the equator and 8 km at the poles. Temperature decreases by 6.4°C with rise of every 1000 m or 1 km. This is called the lapse rate of temperature. Most of the weather phenomena occur in this zone. Eg. – clouds, rainfall, storms etc.

Question 2.
Describe the stratosphere.
Answer:
The second layer of the atmosphere that lies above the troposphere and extends up to 80 km above the earth’s surface is called the stratosphere. In this zone, temperature goes on increasing with increase in height (about 4°C for every 50 km). A significant concentration of ozone gas is found in this layer, known as the Ozonosphere. Stratosphere has very less atmospheric disturbances. Some cirrus clouds form in the lower levels of this layer.

Question 3.
Describe the mesosphere.
Answer:
The third layer of the atmosphere that lies above the stratosphere is known as the mesosphere. This zone is marked by decrease in temperature with height. This is the coldest layer of the atmosphere. Meteors that come from the outer space towards the earth get burnt within this layer.

Question 4.
What are the characteristics of the ozone layer?
Answer:
The ozone layer is a part of the stratosphere. The main characteristics of this layer are :

1. Ozone constitutes about 1% of the stratospheric air.
2. Ozone is produced by the action of solar radiation on ordinary oxygen atoms.
3. Ozone layer acts as a shield, protecting us by absorbing most of the harmful ultra-violet rays of the sun.
4. Density of ozone gas is expressed by the ‘Dobson’ unit (DU). Lowest density of the layer is found in the equatorial region.

Question 5.
What do you mean by ozone depletion and ozone hole.
Answer:
Depletion or breaking of ozone molecules in the atmosphere is known as ozone depletion.

1. Average natural concentration of ozone dropped by 50% in 1987.
2. In some areas, the ozone layer totally disappeared which resulted in formation of ozone-less patches. These hollows are called ozone holes.
3. The chloro fluoro carbons (CFCs) are the chief culprits causing ozone depletion.

Question 6.
Mention the characteristics of the lonosphere.
Answer:
The layer of the atmosphere lying above the mesosphere is called the ionosphere or thermosphere. The characteristics of this layer are :

1. This layer extends up to 500 km above the mesopause.
2. The gases absorb X-rays and Ultra-violet rays and the temperature increases.
3. Radio waves are reflected back from this layer, thus helping in radio communication.
4. Auroras or strange interesting lights are produced in the ionosphere. These are called Aurora Borealis in the northem hemisphere and Aurora Australis in the southern hemisphere.

Answer in details :

Question 1.
Discuss the layers of the atmosphere.
Answer:
[Write about all the layers of the atmosphere discussed previously.]