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.]

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 2.1 Concepts of Atmosphere offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 2.1 Question Answer – Concepts of Atmosphere

Answer in short : 2 Marks

Question 1.
What is atmosphere?
Answer:
The thick blanket of air surrounding the earth, extending to a height of about 10,000 km above its surface, is known as the atmosphere. It is hold in place by the gravitational force of the earth.

Question 2.
What are Aerosols?
Answer:
Aerosols are very fine solid particles that remain suspended in the air. They act as the base of condensation for rainfall, snowfall, fog, dew, mist etc. They absorb solar radiation and keep the atmosphere warm. They are responsible for reflection of sunlight causing dawn and twilight. They also reflect light and make the sky appear blue.

Question 3.
Name the major gases of the atmosphere.
Answer:
The main gases of the atmosphere are : Nitrogen (78.084%), Oxygen (20.946%), Argon (0.934 %), Carbon dioxide (0.033 %).
Other gases present are : Neon, Helium, Krypton, Xenon, Hydrogen, Methane, Nitrous oxide, Radon, Ozone etc. Amongst these, Nitrogen, Argon, Neon, Helium, Krypton and Xenon are known as noble or inert gases.

Question 4.
What are the importances of oxygen in the atmosphere?
Answer:
Oxygen occupies about 21 % of the atmosphere. Importances of this gas are:

1. Oxygen helps to support life.
2. It helps to provide heat and energy in living organisms.
3. It helps in burning of fire.
4. It helps in the process of oxidation.
5. It causes rusting of iron.

Question 5.
Mention the importances of nitrogen gas in the atmosphere.
Answer:
Nitrogen occupies about 78 % of the atmosphere. Its importances are :

• Protein synthesis in living organisms.
• Increasing soil fertility.
• Manufacturing fertilisers.

Question 6.
Mention the importances of carbon dioxide.
Answer:
Carbon dioxide occupies a negligible percentage (0-033 %) in the atmosphere, but it is a very important gas.

1. It helps in photosynthesis and formation of glucose in plants.
2. It helps in carbonation of rocks during weathering.
3. It controls atmospheric temperature.
4. It controls or influences the climate.
5. It helps in weathering of limestone.

Question 7.
What is the homosphere ?
Answer:
According to D. S. Lal, “the term homosphere means the zone of homogenous composition’. It refers to that part of the atmosphere, where the composition is uniform.

Question 8.
What is the heterosphere?
Answer:
The atmosphere above the homosphere up to a height of 10,000 km is not uniform in composition with reference to its chemical composition and proportion. This part of the atmosphere is known as the heterosphere.

Question 9.
Why are the inert gases called so ?
Answer:
Gases like Nitrogen, Argon, Neon, Helium, Krypton and Xenon do not react with the components of atmosphere and the earth’s surface under normal circumstances. Hence they are called ‘inert gases’.

Question 10.
What is density of the atmosphere?
Answer:
The amount of gas molecules or the mass of gas molecules present in a unit volume of the atmosphere is known as the density of the atmosphere.

Answer in briefly : 3 Marks

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

1. Water vapour not only absorbs the sun’s incoming radiation (insolation), but also absorbs the heat radiated back by the earth, thus keeping the atmosphere warm.
2. It helps in formation of clouds, fog, dew, rainfall, snowfall etc.
3. Amount of water vapour influences occurrence of rainfall, snowfall, storms, and other environmental activities.
4. It helps the hydrological cycle to function properly.

Question 2.
Describe the importances of dust particles in the atmosphere.
Answer:
Dust particles mix with the atmosphere from various sources like – soil particles, salt particles from seas, solid particles coming out of cars and chimney smoke, cinder, ash etc. from volcanoes, ash from forest fires etc.
Importances of these particles in the atmosphere are :

• The dust particles act as the base of condensation for the formation of clouds, fog, mist, dew, rainfall, snowfall etc.
• They reflect and refract light.
• They help in occurrence of dawn, twilight and help the sky appear blue.
• They absorb insolation and back radiation from the earth and help to keep the atmosphere warm.

Question 3.
Mention the characteristics of the atmosphere.
Answer:
The main characteristics of the atmosphere are :

1. The atmosphere extends up to 10,000 km above the surface of the earth.
2. Density of the atmosphere reduces with height.
3. This contains the most important components that are inevitable for plant and animal life.
4. The atmosphere is invisible, but its presence can be felt evidently.

Question 4.
What are the characteristics of the ozone layer?
Answer:
Ozone gas is concentrated in the stratosphere at an altitude of 25-50 km above the earth’s surface. This layer is also called the ozonosphere. The characteristics are :

• 90% of ozone gas lies in this layer.
• It filters the ultra-violet rays that comes from the sun.
• It protects the biotic world from damage and disaster.
• Density of ozone gas is expressed in Doloson Unit (DU).
• Density of ozone gas is 250 DU near the equator, 350 DU in the mid latitudes and 450 DU in the polar regions.

Answer in details : 5 Marks

Question 1.
Name the main components of the atmosphere and discuss about them.
Answer:
The components of the atmosphere can be classified into two parts :
(a) Permanent components : The permanent components mainly constitute the gaseous elements those proportion does not change in the atmosphere.
They are : Nitrogen (78.084%), Oxygen (20.946%), Argon (0.934%), Carbon dioxide (0.033 %) and other gases like Nitrogen, Neon, Helium, Hydrogen, Xenon, Krypton, Methane, Radon, Ozone etc.

(b) Variable components : These include :
i) Water vapour : Amount of water vapour varies from place to place, time to time and depends on factors like heat, presence of water bodies, wind speed, humidity etc.

ii) Dust particles : Tiny solid particles coming from dust, salt grains, pollen grains, smoke, soot etc. remain suspended in the air in different amounts in different places. These are also called aerosols.

iii) Carbon dioxide : CO₂ is an important variable gas. Currently it constitutes about 0.03 %. of the atmosphere. It is a potent green house gas and plays a vital role in controlling the earth’s surface temperature.

Question 2.
Classify the layers of the atmosphere according to temperature.
Answer:
The atmosphere has been classified into five layers by Pattersen according to temperature.
i) Troposphere : The troposphere extends up to 18 km in the equatorial region to 7-8 km in the polar region above the earth’s surface. Temperature of this layer reduces by 6.4°C for every 1000 ~m rise in altitude. The lowest temperature

recorded here is -80°c at the highest limits of the troposphere near the equator.

ii) Stratosphere: This layer is above the troposphere, and is separated by the tropopause. Temperature of this layer goes on increasing with rise in altitude. It spreads up to 50 km above the earth’s surface. Temperature reaches to 0°C at the highest levels of the stratosphere. This layer is void of clouds and rainfall. A concentrated layer of ozone gas is found within this layer.

iii) Mesosphere : After the stratosphere, the mesosphere lies up to 80 km above the earth’s surface. This is the last limit of the homosphere. Temperature decreases with increase in altitude. This layer lies between the stratopause and the mesopause.

iv) Ionosphere or Thermosphere : This layer spreads up to 500 km from the earth’s surface after the mesopause. Temperature increases rapidly in this layer with rise in altitude, and reaches about 1200°C at the upper limits. In this layer, constant interaction of ultra violet rays, x-rays, α-rays, β-rays and γ-rays cause ionisation of the gases.

v) Exosphere : This layer spreads from 500-750 km above the earth’s surface.

Question 3.
Differentiate between the Homosphere and the Heterosphere.
Answer:

Homosphere	Heterosphere
i. The ratio of component gases of the atmosphere remains more or less same up to 88 km altitude. This layer is called the homosphere.	i. The ratio of component gases of the atmosphere does not remain the same beyond 88 km altitude. This layer is called the heterosphere.
ii. It spreads from 0-88 km above the earth’s surface.	ii. It spreads from 88-10,000 km above the earth’s surface.
iii. It comprises the troposphere, stratosphere, mesosphere and parts of the thermosphere.	iii. It comprises parts of thermosphere, the exosphere and magnetosphere.
iv. It consists of gases, water vapour and dust particles.	iv. It consists of very little traces of water vapour and dust particles. The gases mostly lie in ionised forms.
v. All the weather conditions and changes occur within 6 km of the homosphere.	v. No weather changes are noticed in the heterosphere.
vi. Lower layers of the homosphere support life and related activities. The ozone layer protects the earth from sun’s harmful ultraviolet rays.	vi. The ionised gases of the heterosphere help in transmission of radio waves, thus helping to run mobiles, wireless sets, radios and other devices.

Multiple Choice Questions (MCQ) : 1 Mark

Question 1.
The tropopause occurs at the equator at a height of :
(A) 5 km.
(B) 20 km.
(C) 18 km.
(D) 25 km.
Answer:
(C) 18 km.

Question 2.
97 % of the atmosphere lies within _____ km. of the surface of the earth :
(A) 50 km.
(B) 29 km.
(C) 5 km.
(D) 15 km.
Answer:
(B) 29 km.

Question 3.
The lower layer lonosphere is known as :
(A) Troposphere
(B) Stratosphere
(C) Ozonosphere
(D) Thermosphere
Answer:
(D) Thermosphere

Question 4.
The Mediterranean region receives rainfall :
(A) From trade winds in summer
(B) From trade winds in winter
(C) From westerlies in winter
(D) By convection in summer
Answer:
(C) From westerlies in winter

Question 5.
The atmospheric layer which reflects radio waves is called :
(A) Exosphere
(B) Stratosphere
(C)Troposphere
(D)Thermosphere
Answer:
(C)Troposphere

Question 6.
Atmosphere gets heated up :
(A) In the early morning
(B) At mid day
(C) At 2:00 pm.
(D) In the late evening
Answer:
(C) At 2:00 pm.

Question 7.
The most important component of the atmosphere which causes many weather phenomena is :
(A) Oxygen
(B) Carbon dioxide
(C) Nitrogen
(D) Water vapour
Answer:
(D) Water vapour

Question 8.
The lower layer of the atmosphere is known as :
(A) Mesosphere
(B) Stratosphere
(C) Ionosphere
(D) Troposphere
Answer:
(D) Troposphere

Question 9.
Tropopause is the zone that separates :
(A) Earth’s surface and Troposphere
(B) Troposphere and Stratosphere
(C) Stratosphere and lonosphere
(D) Earth’s surface and lonosphere
Answer:
(B) Troposphere and Stratosphere

Question 10.
Ionosphere is :
(A) The lowest region of the atmosphere
(B) The highest region of the atmosphere
(C) The middle most region of the atmosphere extending from 40 km. to 75 km.
(D) None of the above
Answer:
(B) The highest region of the atmosphere

Question 11.
The tropopause is situated at a height of over the equator
(A) 10 km.
(B) 15 km.
(C) 18 km.
(D) 22 km.
Answer:
(C) 18 km.

Question 12.
Most of the weather phenomena take place in the :
(A) Stratosphere
(B) Ionosphere
(C) Troposphere
(D) Mesosphere
Answer:
(C) Troposphere

Question 13.
________ of the effective atmosphere is found up to the height of 29 km.:
(A) 29 %
(B) 35 %
(C) 90 %
(D) 97 %
Answer:
(D) 97 %

Question 14.
Percentage of argon in the atmosphere is :
(A) 1 %
(B) 1.5 %
(C) 0.30 %
(D) 0.93 %
Answer:
(D) 0.93 %

Question 15.
Which one of the following is lowermost layer?
(A) Stratosphere
(B) Troposphere
(C) Troposphere or Stratosphere
(D) It is not certain
Answer:
(B) Troposphere

Question 16.
Normal Lapse rate is supposed to be:
(A) 6.5°C per 100m
(B) 6.5°C per 10m
(C) 6.5°K per 100m
(D) 6.0°K per 100m
Answer:
(A) 6.5°C per 100m

Question 17.
The average height of the troposphere over the poles is around :
(A) 16 km
(B) 14 km
(C) 8 km
(D) 6 km
Answer:
(D) 6 km

Question 18.
Medium and high frequency radio waves are reflected by which layer?
(A) E layer
(B) G layer
(C) F layer
(D) All of these
Answer:
(C) F layer

Question 19.
Isobars are :
(A) The lines of equal atmospheric pressure
(B) The lines of unequal atmospheric pressure
(C) The parallel lines of atmospheric pressure
(D) None of the above
Answer:
(A) The lines of equal atmospheric pressure

Question 20.
What is the characteristic of planetary winds:
(A) These flow from the belts of high pressure to the belts of low pressure
(B) These flow from the belts of low pressure to the belt of high pressure
(C) These do not flow to any centre of pressure
(D) None of these
Answer:
(A) These flow from the belts of high pressure to the belts of low pressure

Question 21.
Wind in the southern hemisphere deflects towards left :
(A) Due to rotation of the earth
(B) Due to temperature
(C) Due to heating
(D) None of these
Answer:
(A) Due to rotation of the earth

Question 22.
The instrument used for measuring the atmospheric pressure is called:
(A) Barometer
(B) Hygrometer
(C)Altimeter
(D) Thermometer
Answer:
(A) Barometer

Question 23.
The mountaineers climbing the high peaks carry:
(A) Helium
(B) Nitrogen
(C) Hydrogen
(D) Oxygen
Answer:
(D) Oxygen

Question 24.
The sub-tropical high pressure belts are also known as :
(A) Doldrums
(B) Roaring forties
(C) Torrid zone
(D) Horse latitudes
Answer:
(B) Roaring forties

Question 25.
Besides the local winds and permanent winds, another type of winds are :
(A) Prevailing winds
(B) Horizontal winds
(C) Vertical winds
(D) Periodic winds
Answer:
(D) Periodic winds

Question 26.
If the incoming solar radiation is 100 % then scattering by dust particles is :
(A) 27 %
(B) 2 %
(C) 6 %
(D) None of these
Answer:
(C) 6 %

Question 27.
The amount of heat needed to raise the temperature of one gram of substance by 1°C is called :
(A) Specific heat
(B) Relative heat
(C) Absolute heat
(D) None of these
Answer:
(A) Specific heat

Question 28.
Horse latitudes are found between the latitudes :
(A) 5°N to 5°S
(B) 25°-35° in both the hemisphere
(C) 30°-45° in both the hemisphere
(D) None of these
Answer:
(B) 25°-35° in both the hemisphere

Question 29.
The zone of _____ wind is also known as Hadley cells.
(A) Westerly
(B) Easterly
(C) Trade
(D) None of these
Answer:
(C) Trade

Question 30.
Which type of rainfall is called relief rainfall ?
(A) Convectional
(B) Orographic
(C) Cyclonic
(D) All of these
Answer:
(B) Orographic

Question 31.
Which of the following instruments is used for measuring the temperature?
(A) Barometer
(B) Thermometer
(C) Hydrometer
(D) Hygrometer
Answer:
(B) Thermometer

Question 32.
Anemometer is used to measure :
(A) The velocity of the earth
(B) The velocity of the waves
(C) The velocity of the winds
(D) The velocity of earthquake waves
Answer:
(C) The velocity of the winds

Question 33.
The actual mass of water vapour per unit volume of air is known :
(A) Relative humidity
(B) Absolute humidity
(C) Specific humidity
(D) Degree of saturation
Answer:
(B) Absolute humidity

Question 34.
The prevailing north-western westerly winds which blow vigorously between 40° and 60° south latitudes throughout the year are known:
(A) Sirocco
(B) Roaring forties
(C) Harmattan
(D) Pampero
Answer:
(B) Roaring forties

Question 35.
About 34 per cent of insolation being returned to space as short waves are known as :
(A) Effective solar radiation
(B) The earth’s Albedo
(C) Heat Transfer
(D) Terrestrial heat balance
Answer:
(B) The earth’s Albedo

Question 36.
The boundary zone developed at or near the mass of warm air where an advancing cold air strikes and forces the warm air upward is called :
(A) Warm front
(B) Cold front
(C) Occuluded front
(D) Warm air mass
Answer:
(B) Cold front

Question 37.
The rate of temperature decreases (C°) in the atmosphere per 1000 metre ascent is :
(A) 3.6° C
(B) 6.4° C
(C) 7.4° C
(D) 8.6° C
Answer:
(B) 6.4° C

Question 38.
Inversion of temperature is :
(A) Increase of temperature with altitude
(B) Decrease of temperature with altitude
(C) Uniform temperature
(D) Decrease of temperature with latitudes
Answer:
(A) Increase of temperature with altitude

Question 39.
The albedo of earth is :
(A) 25 %
(B) 35 %
(C) 45 %
(D) 55 %
Answer:
(B) 35 %

Question 40.
The total annual insolation is greatest at –
(A) The tropic of Cancer
(B) The tropic of Capricorn
(C) The equator
(D) The arctic circle
Answer:
(D) The arctic circle

Question 41.
The dry adiabatic lapse rate is :
(A) 6.4°C
(B) 10°C
(C) 8.5°C
(D) 2°C
Answer:
(B) 10°C

Question 42.
Jet stream is a :
(A) Warm Current
(B) Cold Current
(C) Local Wind
(D) Upper air westerlies
Answer:
(D) Upper air westerlies

Question 43.
The type of rainfall common at equatorial region is :
(A) Convectional
(B) Orographic
(C) Cyclonic
(D) Relief
Answer:
(A) Convectional

Question 44.
Doldrum is a zone of :
(A) Intertropical Convergence
(B) Intertropical Divergence
(C) Local wind
(D) Frontolysis
Answer:
(A) Intertropical Convergence

Question 45.
The highest temperature is recorded by :
(A) Mercurial thermometer
(B) Hot thermometer
(C)Alcohol thermometer
(D) Minimum thermometer
Answer:
(A) Mercurial thermometer

Question 46.
The lowest temperature is recorded by :
(A) Maximum thermometer
(B) Mercurial thermometer
(C) Alcohol thermometer
(D) None of these
Answer:
(C) Alcohol thermometer

Question 47.
What is the name of the scale meant for recording weather conditions?
(A) Fahrenheit
(B) Barometer
(C) Hydrometer
(D) Opisometer
Answer:
(A) Fahrenheit

Question 48.
Another scale used for recording weather conditions is known as :
(A) Hygrometer
(B) Hydrometer
(C) Opisometer
(D) Centigrade
Answer:
(D) Centigrade

Question 49.
Which of the following components of the atmosphere has increased during the last 200 years?
(A) Oxygen
(B) Water vapour
(C) Carbon dioxide
(D) Nitrogen
Answer:
(C) Carbon dioxide

Question 50.
The velocity of wind is recorded by :
(A) altimeter
(B) Barometer
(C) Anemometer
(D) Aneroid barometer
Answer:
(C) Anemometer

Question 51.
Horse latitudes lie :
(A) In the vicinity of 30° latitude both north and south of the equator
(B) In the vicinity of 50° latitude both north and south of the equator
(C) Between 50° and 60° latitude both north and south of equator
(D) None of these
Answer:
(A) In the vicinity of 30° latitude both north and south of the equator

Question 52.
When warm air moves into a region of cold air it leads to the formation of :
(A) Cold front
(B) Warm front
(C) Cyclone
(D) Anticyclone
Answer:
(B) Warm front

Question 53.
Hurricanes are generally :
(A) Active over land
(B) Active over the sea
(C) Travelling in families
(D) Dust storms
Answer:
(B) Active over the sea

Question 54.
The tropical cyclones of the Bay of Bengal are usually called :
(A) Typhoons
(B) Hurricanes
(C) Depressions
(D) Willy willy
Answer:
(A) Typhoons

Question 55.
Jet Stream blows :
(A) From west to east
(B) From east to west
(C) From north to south
(D) None of these
Answer:
(A) From west to east

Question 56.
In which region does rainfall occur throughout the year?
(A) Equatorial region
(B) Polar region
(C) Sub-polar region
(D) Middle-latitude region
Answer:
(A) Equatorial region

Question 57.
China type (Cw) has dry winter season because :
(A) Cool dry winds blow from interior of the continent
(B) There are no clouds
(C) Temperature is low
(D) Humidity is low
Answer:
(A) Cool dry winds blow from interior of the continent

Question 58.
Tropical deserts receive scanty rainfall because:
(A) They are away from the equator
(B) They do not have clouds
(C) Trade winds blow from the hot interior of the continent
(D) Cool currents blow along the coast
Answer:
(C) Trade winds blow from the hot interior of the continent

Question 59.
Which of the following is not a tropical desert:
(A) Kalahari
(B) Atacama
(C) Arabia
(D) Mongolia
Answer:
(D) Mongolia

Question 60.
Conduction is a process :
(A) That conducts heat from warmer to the cooler region until the two objects coming into contact get the same temperature
(B) That conducts heat from cooler to the warmer region
(C) That does not conduct heat to any of the objects coming into contact
(D) None of the above
Answer:
(A) That conducts heat from warmer to the cooler region until the two objects coming into contact get the same temperature

Question 61.
Humidity is the result of :
(A) Evaporation
(B) Transpiration
(C) Presence of heat
(D) Presence of moisture content in the air
Answer:
(D) Presence of moisture content in the air

Question 62.
Specific humidity is :
(A) The indicator of density of water vapour
(B) The maximum water content existing in the atmosphere
(C) It is the ratio of the mass of water vapour present to the total mass of air
(D) None of the above
Answer:
(C) It is the ratio of the mass of water vapour present to the total mass of air

Question 63.
What is relative humidity ?
(A) It is the ratio of specific humidity
(B) It is the indicator of moisture content of atmosphere
(C) It is the indicator of density of water vapour
(D) None of the above
Answer:
(A) It is the ratio of specific humidity

Question 64.
Annual range of temperature is maximum in :
(A) Equatorial region
(B) Sub-tropical region
(C) Middle latitudes
(D) Polar regions
Answer:
(C) Middle latitudes

Question 65.
The winds blowing from subtropical high pressure to sub-polar low pressure are :
(A) Westerlies
(B) Easterlies
(C) Polar winds
(D) Jet Stream
Answer:
(B) Easterlies

Question 66.
Doldrum belt is the region of :
(A) High pressure and strong winds
(B) Moderate pressure
(C) Low pressure and calm conditions
(D) None of these
Answer:
(C) Low pressure and calm conditions

Question 67.
Animometer is :
(A) An instrument that measures the wind speed
(B) An instrument that measures the air masses
(C) An instrument that measures speed
(D) An instrument that measures velocity
Answer:
(A) An instrument that measures the wind speed

Question 68.
Trade winds are :
(A) Moisturous
(B) Hot and wet
(C) Dry
(D) Wet
Answer:
(C) Dry

Question 69.
Beaufort scale is used to measure :
(A) Air pressure
(B) Wind velocity
(C) Wind direction
(D) Humidity
Answer:
(B) Wind velocity

Question 70.
The Torrid Zone lies between :
(A) The Equator and the Tropic of Cancer
(B) The Equator and the Tropic of Capricorn
(C) The Tropic of Cancer and the Tropic of Capricorn
(D) Precipitation and natural vegetation
Answer:
(C) The Tropic of Cancer and the Tropic of Capricorn

Question 71.
Nitrogen and Oxygen constitute of the total gaseous composition of the atmosphere.
(A) 93 %
(B) 95 %
(C) 97 %
(D) 99 %
Answer:
(D) 99 %

Question 72.
Which of the following is a Greenhouse gas ?
(A) Carbondioxide
(B) Ozone
(C) Oxygen
(D) Nitrogen
Answer:
(A) Carbondioxide

Question 73.
Most of the ultraviolet rays one absorbed by
(A) Hydrogen
(B) Nitrogen
(C) Ozone
(D) Carbondioxide
Answer:
(C) Ozone

Question 74.
________ is a permanent gas in the atmosphere.
(A) Carbondioxide
(B) Ozone
(C) Nitrogen
(D) Hydrogen
Answer:
(C) Nitrogen

Question 75.
Atmospheric water vapour content is highest in the
(A) Temperate region
(B) Polar region
(C) Equatorial region
(D) Tropical region
Answer:
(D) Tropical region

Question 76.
The English word ‘atmosphere’ comes from the green word ‘atmos’, which means-
(A) Air
(B) Vapour
(C) Evaporation
(D) Envelop of gases
Answer:
(B) Vapour

Question 77.
The sky appears blue due to selective scattering of solar radiation by-
(A) Salt particles
(B) Dust particles
(C) Both A and B
(D) None of these
Answer:
(B) Dust particles

Question 78.
Troposphere contains about ______ of the total gaseous mars of the atmosphere.
(A) 70 %
(B) 75 %
(C) 80 %
(D) 85 %
Answer:
(B) 75 %

Question 79.
Which of the following is also called the convective region?
(A) lonosphere
(B) Ozonosphere
(C) Troposphere
(D) Mesosphere
Answer:
(C) Troposphere

Question 80.
The wind velocity increases with height in the –
(A) Troposphere
(B) Stratosphere
(C) Stratopause
(D) lonosphere
Answer:
(A) Troposphere

Question 81.
The thickness of the stratosphere is highest at the –
(A) Poles
(B) Tropics
(C) Equator
(D) All of these
Answer:
(A) Poles

Question 82.
Which gas protects us from the harmful ultraviolet rays ?
(A) Nitrogen
(B) Oxygen
(C) Ozone
(D) Carbondioxide
Answer:
(C) Ozone

Question 83.
The credit for the discovery of ionosphere goes to –
(A) Napier Shaw
(B) Picardy
(C) Kennelly and Heaviside
(D) Teisserence de Bort
Answer:
(C) Kennelly and Heaviside

Question 84.
During the winter season, the stratosphere is warmest between the latitudes
(A) 50°-60°
(B) 50°-65°
(C) 50°-70°
(D) 50°-75°
Answer:
(A) 50°-60°

Question 85. ‘Aurora Borealis’ is produced in the
(A) Exosphere
(B) Ionosphere
(C) Mesosphere
(D) Stratosphere
Answer:
(B) Ionosphere

Question 86.
Match the following

Answer:

Question 87.
helps to keep the temperature of the earth’s surface moderate.
(A) Gases
(B) Water vapour
(C) Particulate matter
(D) All of these
Answer:
(B) Water vapour

Question 88.
Which of the following is an important feature of the Troposphere?
(A) It is isothermal in character
(B) There is maximum concentration of ozone
(C) There is a decrease of temperature with increase in altitude at a mean lapse rate of about 6.5°C
(D) There is a steep rise in temperature
Answer:
(C) There is a decrease of temperature with increase in altitude at a mean lapse rate of about 6.5°C

Question 89.
The outermost layer of the atmosphere is known as
(A) Exosphere
(B) lonosphere
(C) Mesosphere
(D) Ozonosphere
Answer:
(A) Exosphere

Question 90.
The gases which are predominant in the exosphere are
(A) Hydrogen and Neon
(B) Hydrogen and Ozone
(C) Hydrogen and Methane
(D) Hydrogen and Helium
Answer:
(D) Hydrogen and Helium

Question 91.
Troposphere, Stratosphere and Mesosphere are subdivisions of the
(A) Homosphere
(B) Heterosphere
(C) Chemosphere
(D) Pyrosphere
Answer:
(A) Homosphere

Question 92.
The atmosphere receives most of its energy from
(A) Sun
(B) Long wave terrestrial radiation
(C) Albedo
(D) Short wave terrestrial radiation
Answer:
(A) Sun

Question 93.
The transfer of heat through the molecules of matter in any body is called
(A) Radiation
(B) Convection
(C) Conduction
(D) Advection
Answer:
(B) Convection

Question 94.
The process of transfer of energy from one body to another without the aid of any material is called –
(A) Conduction
(B) Radiation
(C) Convection
(D) Advection
Answer:
(C) Convection

Question 95.
What percentage of outgoing longwave terrestrial radiation is absorbed by atmosphere?
(A) 60 %
(B) 70 %
(C) 80 %
(D) 90 %
Answer:
(D) 90 %

Question 96.
The increase in the concentration of CO₂ in the atmosphere will increase the
(A) Heat
(B) Greenhouse effect
(C) Radiation
(D) Evaporation
Answer:
(B) Greenhouse effect

Question 97.
The earth’s surface recelves maximum solar energy at about
(A) 11: 00 am
(B) 12 Noon
(C) 1: 00 pm
(D) 2: 00 pm
Answer:
(B) 12 Noon

Question 98.
The thermal inversion in the upper air is caused by the presence of
(A) Carbondioxide
(B) Ozone layer
(C) Water vapour
(D) None of these
Answer:
(B) Ozone layer

Question 99.
Which of the following surface receives very low insolation ?
(A) Snow cover
(B) Sand
(C) Black soil
(D) Forest
Answer:
(A) Snow cover

Question 100.
The horizontal distribution of temperature is represented and studied with the help of –
(A) Isotherms
(B) Isobars
(C) Isohyte
(D) Isohayline
Answer:
(A) Isotherms

Question 101.
The weight of air on unit area of the earth is called
(A) Air weight
(B) Air pressive
(C) Air mass
(D) Air volume
Answer:
(B) Air pressive

Question 102.
The atmospheric pressure is maximum at the
(A) Coastal areas
(B) Interior parts of continents
(C) Sea level
(D) All of these
Answer:
(C) Sea level

Question 103.
The standard air pressure at sea level is –
(A) 1018.25 m
(B) 1021.25 m
(C) 1013.25 m
(D) 1015.25 m
Answer:
(C) 1013.25 m

Question 104.
Which of the following pressure belt is thermally inducted?
(A) Subtropical high pressure belt
(B) Equatorial low pressure belt
(C) Subpolar low pressure belt
(D) Both ‘A’ and ‘C’
Answer:
(B) Equatorial low pressure belt

Question 105.
The winds blowing almost in the same direction throughout the year are called
(A) Prevailing winds
(B) Seasonal winds
(C) Local winds
(D) Variable winds
Answer:
(A) Prevailing winds

Question 106.
Winds blowing in a particular locality are called
(A) Seasonal winds
(B) Local winds
(C) Mountain winds
(D) Land and sea breeze
Answer:
(B) Local winds

Question 107.
Which winds are famous for there steady direction and wind speed?
(A) Westerlies
(B) Easterlies
(C) Polar winds
(D) Trade winds
Answer:
(D) Trade winds

Question 108.
The subtropical high pressure belt is the source of –
(A) Polar winds
(B) Trade winds
(C) Local winds
(D) Westerlies
Answer:
(B) Trade winds

Question 109.
The continent having the greatest monsoonal influence is –
(A) North America
(B) Asia
(C) South America
(D) Australia
Answer:
(B) Asia

Question 110.
Which of the following wind prevails on the eastern slopes of the Rocky mountains in Wyoming and Montana?
(A) Santa Ana
(B) Mistral
(C) Sirocco
(D) Chinook
Answer:
(D) Chinook

Question 111.
Which of the following is an intensely hot and dry wind of the Asiatic and African deserts?
(A) Khamsin
(B) Sirocco
(C) Simoom
(D) Harmatian
Answer:
(C) Simoom

Question 112.
Which of the following is a cold north-western wind that blows towards the western mediteranean basin from higher elevations?
(A) Mistral
(B) Bora
(C) Blizzard
(D) Harmattan
Answer:
(A) Mistral

Question 113.
The most important form of suspended water droplets caused by condensation is
(A) Fog
(B) Ice
(C) Cloud
(D) Frost
Answer:
(C) Cloud

Question 114.
is the most common form of precipitation
(A) Snow
(B) Rainfall
(C) Sleet
(D) Hail
Answer:
(B) Rainfall

Question 115.
Which of the following is a warm weather phenomena associated with lightning and thunder?
(A) Convectional rainfall
(B) Orographic rainfall
(C) Frontal rainfall
(D) All of these
Answer:
(A) Convectional rainfall

Question 116.
Which of the following rainfall occur due to ascent of air, forced by mountain barrier?
(A) Convectional rainfall
(B) Orographic rainfall
(C) Cyclonic rainfall
(D) All of these
Answer:
(B) Orographic rainfall

Question 117.
Indian monsoon is the best example of
(A) Convectional rainfall
(B) Cyclonic rainfall
(C) Orographic rainfall
(D) None of these
Answer:
(C) Orographic rainfall

Question 118.
Southern plateau in the east of Western Ghats is the example of
(A) Inversion of rainfall
(B) Cloud instability
(C) Maximum rainfall line
(D) Rain shadow area
Answer:
(D) Rain shadow area

Question 119.
The precipitation associated with cold fronts is always in the form of
(A) Snow
(B) Drizzle
(C) Thunder shower
(D) Sleet
Answer:
(C) Thunder shower

Question 120.
Most of the rains of temperate regions are received through
(A) Cyclonic rainfall
(B) Orographic rainfall
(C) Convectional rainfall
(D) None of these
Answer:
(A) Cyclonic rainfall

Question 121.
Which of the following pressure belt is called ‘Horse latitude’ ?
(A) Polar high pressure belt
(B) Subpolar low pressure belt
(C) Subtropical high pressure belt
(D) Equatorial low pressure belt
Answer:
(C) Subtropical high pressure belt

Question 122.
Which of the following winds blows parallel to the isobars, generally at a height of 600 m ?
(A) Gradient wind
(B) geostrophic wind
(C) Invariable wind
(D) Surface wind
Answer:
(B) geostrophic wind

Question 123.
The direction of surface wind is usually controlled by
(A) Pressure gradient
(B) Rotation of the earth
(C) Deflection forces
(D) Both ‘A’ and ‘B’
Answer:
(D) Both ‘A’ and ‘B’

Question 124.
The zone extending 5°N to 5°S along the equator is called
(A) Doldrums
(B) Horse latitudes
(C) Trade wind
(D) Westerlies
Answer:
(A) Doldrums

Question 125.
Winter precipitation in the Northern part of India is an example of ______ rainfall.
(A) Orographic
(B) Monsoonal
(C) Convectional
(D) Cyclonic
Answer:
(D) Cyclonic

Question 126.
The monsoon region is located in the ______ rainfall zero.
(A) Mediterranean
(B) Trade wind
(C) Subtropical
(D) Midlatitude
Answer:
(B) Trade wind

Question 127.
______ is an example of atmospheric disturbance.
(A) Rain
(B) Cyclone
(C) Fronts
(D) Winds
Answer:
(B) Cyclone

Question 128.
Temperate cyclones are formed where
(A) Contrasting air masses generally meet
(B) Same air masses generally meet
(C) No air masses meet
(D) None of these
Answer:
(A) Contrasting air masses generally meet

Question 129.
Which of the following is a real temperate cyclone?
(A) Dynamic cyclone
(B) Thermal cyclone
(C) Secondary cyclone
(D) Both ‘A’ and ‘B’
Answer:
(A) Dynamic cyclone

Question 130.
The diameter of the temperate cyclone varies from
(A) 160-3200 km
(B) 170-3400 km
(C) 180-3600 km
(D) 190-3800 km
Answer:
(A) 160-3200 km

Question 131.
The vertical extent of an average cyclone is about
(A) 10-12 km
(B) 12-14 km
(C) 14-16 km
(D) 16-18 km
Answer:
(A) 10-12 km

Question 132.
Most of the cyclones and anticyclones in the westerly wind belt move from –
(A) East to West
(B) West to East
(C) North to East
(D) South to West
Answer:
(B) West to East

Question 133.
On an average, diameter of tropical cyclone ranges between
(A) 80-500 km
(B) 80-400 km
(C) 80-300 km
(D) 80-200 km
Answer:
(C) 80-300 km

Question 134.
Tropical cyclones affect the
(A) Interior areas of continents
(B) Coastal areas of continents
(C) Peninsular areas of continents
(D) Central areas of continents
Answer:
(B) Coastal areas of continents

Question 135.
Tropical cyclone develops in the regions
(A) of high latitudes
(B) of mid-latitudes
(C) Along the equator
(D) Lying between the tropics of Cancer and Capricorn
Answer:
(D) Lying between the tropics of Cancer and Capricorn

Question 136.
Tropical cyclones move from East to West under the influence of
(A) Easterlies
(B) Westerlies
(C) Polar winds
(D) Trade winds
Answer:
(D) Trade winds

Question 137.
________ develops in the Caribbean Sea and North Pacific Ocean during summer months.
(A) Hurricanes or Typhoons
(B) Tropical disturbances
(C) Tropical depressions
(D) Tropical storms
Answer:
(B) Tropical disturbances

Question 138.
_______ develops frequently in the Bay of Bengal and Arabian sea during the summer season.
(A) Tropical storms
(B) Tropical depressions
(C) Tropical disturbances
(D) Hurricanes or Typhoons
Answer:
(A) Tropical storms

Question 139.
Match the following :

Answer:

Question 140.
Tropical cyclones originate over warm oceans having average surface temperature of ______ during summer.
(A) 27° C
(B) 30° C
(C) 33° C
(D) 36° C
Answer:
(A) 27° C

Question 141.
Tropical cyclone influence the climatic conditions of India between
(A) April and September
(B) April and October
(C) April and November
(D) April and December
Answer:
(D) April and December

Question 142.
Which of the following is a funnel-shaped cyclone with thick clouds?
(A) Tornadoes
(B) Hurricanes
(C) Thunderstorms
(D) Depressions
Answer:
(A) Tornadoes

Question 143.
Auticyclones are vast areas of high pressure with a system of _______ surface winds.
(A) Diverging
(B) Converging
(C) Deformative
(D) Diffusing
Answer:
(A) Diverging

Question 144.
Auticyclones are indicative of –
(A) Humid weather
(B) Dry weather
C) Rainy weather
(D) Hot and dry weather
Answer:
(B) Dry weather

Question 145.
The diameter of anticyclones of mid-latitudes is about
(A) 2000 km
(B) 3000 km
(C) 4000 km
(D) 5000 km
Answer:
(B) 3000 km

Fill in the blanks : 1 Mark

1. Ozone layer was discovered by ________.
2. ‘El Nino’ means ________.
3. Barometer was discovered by ________.
4. A _____ is used to measure air pressure.
5. Air pressure is measured by the unit ________.
6. A ______ is used to measure aire temperature.
7. A ________ is used to measure humidity of air.
8. The westerlies are referred to as roaring forties along the ______ latitude.
9. the westerlies are referred to screaming sixties along the _______ latitude.
10. The _______ is a comparatively calur layer of atmosphere.
11. Van Allen radiation belt can be seen at an altitude of ________.
12. The temperature of the upper part of the mesosphere is about ________.
13. ________ are the chief ozone destroying gases.
14. The radio waves are reflected back to the earth from the ________.
15. Sea breeze blows during ________.
16. The _______ helps to detect rapid change in air pressure.
17. Pompero blows in the valley of river ________.
18. The _______ helps to measure wind speed.
19. In the tropical region, the deserts have been created on the side of the _______ continents.
20. The land breeze blows with the greatest speed during the ________.
21. If pressure gradient increases, wind speed ________.
22. By ferrel’s law, winds deflect towards the in the _______ southern hemisphere.
23. The mediterranearn region received rainfall during ________.
24. the cold wind blowing along the Adriatic Sea coast during winter is called ________.
25. The winds are called ‘snow eaters’.
26. The ________ winds are the heavy winds that descend along the mountain slopes.
27. Connectional rainfall occurs from _______ clouds.
28. Smoke and fog together produce ________.
29. Relative humidity is measured by the instrument called ________.
30. _______ is a rain shadow area in India.
Answer:
1. Charles Fabry and Henri Buisson
2. Christ child
3. Torricelli
4. Barometer
5. Milibar
6. Thermometer
7. Hygrometer
8. 40°
9. 60°
10. Stratosphere
11. 4000 km
12. (-) 93°C
13. CFCs
14. Ionosphere
15. Day time
16. Barogram
17. Rhine
18. Anemometer
19. Western
20. Early morning
21. Increases
22. Left
23. Winter
24. Bora
25. Chinook
26. Katabatic
27. Cumulonimbus
28. Smog
29. Psychrometer
30. Shillong/Eastern slope of Western Ghats

State True or False : 1 Mark

1. The CO₂ absorbs the ultraviolet rays of the sun. [ ]
2. The water vapour present in the atmosphere leads to the scattering of light. [ ]
3. Hydrogen gas concentrates at an altitude of 200-1100 km above the earth’s surface. [ ]
4. The meteors coming from outer space one burnt in the mesosphere of the earth’s atmosphere. [ ]
5. The jet planes fly through the stratosphere. [ ]
6. The thickness of the troposphere is about 8 km near the equator. [ ]
7. CFCs are emitted by refrigerators, air conditioners etc. [ ]
8. The tropopause lies between the stratosphere and mesosphere. [ ]
9. The boiling point of water by the Fahrenheit scale is 212°F. [ ]
10. High pressure prevails in the Arctic circle region. [ ]
11. Orographic rainfall occurs in the windward slope of the mountains. [ ]
12. In tropical regions, cyclones occur due to formation of fronts. [ ]
13. Inversion of temperature occurs in the stratosphere. [ ]
14. A local wind named Fohn blows in Alps mountainous region. [ ]
15. Due to the coriolis force, winds are deflected towards the right in the northern hemisphere, and towards the left in the southern hemisphere. [ ]
16. The 30°-35° latitudes are also known as horse latitudes. [ ]
17. The jet stream influences the monsoon winds. [ ]
18. Low pressure prevails in the centre of anticyclones. [ ]
19. The centre of the cyclone is known as an eye. [ ]
20. The westerlies blow with higher speed in the southern hemisphere than the northern hemisphere. [ ]
21. The anticyclone moves in a clockwise direction in the northern hemisphere. [ ]
22. Cyclones commonly occur in China. [ ]
Answer:
1. Flase
2. Flase
3. Flase
4. True
5. True
6. Flase
7. True
8. Flase
9. True
10. Flase
11. True
12. Flase
13. True
14. True
15. True
16. True
17. True
18. Flase
19. True
20. True
21. True
22. Flase

Answer in few words : 1 Mark

Question 1.
What is the envelop of air around the earth called?
Answer:
Atmosphere.

Question 2.
Which gas is needed by green plants?
Answer:
Carbon dioxide.

Question 3.
Which gas saves us from the harmful Ultraviolet rays ?
Answer:
Ozone.

Question 4.
Which is the densest layer of the atmosphere ?
Answer:
Troposphere.

Question 5.
What lies between the stratosphere and mesosphere?
Answer:
The Stratopause.

Question 6.
Which force is responsible for exertion of atmospheric pressure on the earth’s surface?
Answer:
The gravitational force of the earth.

Question 7.
What is the horizontal movement of air called ?
Answer:
Wind.

Question 8.
What is the other name for permanent winds ?
Answer:
Planetary winds.

Question 9.
Name two winds blowing in opposite directions.
Answer:
The easterlies or trade winds and the westerlies.

Question 10.
What type of a wind is the monsoon wind ?
Answer:
Periodic wind.

Question 11.
How is humidity represented ?
Answer:
In percentage.

Question 12.
By which process does water vapour in the air change into water ?
Answer:
Condensation.

Question 13.
What is ‘dew’?
Answer:
Tiny droplets of water that remain suspended in the air.

Question 14.
What is sleet?
Answer:
Rain and snow falling together.

Question 15.
Name two rain-bearing clouds.
Answer:
Cumulus and nimbus.

Question 16.
Where does relief rainfall occur?
Answer:
Windward side of mountains.

Question 17.
Does warm air hold more or less water vapour ?
Answer:
More water vapour.

Question 18.
Does speedy winds increase the rate of evaporation?
Answer:
Yes.

Question 19.
What is a saturated air ?
Answer:
Air that holds the maximum amount of water vapour that it can hold.

Question 20.
Name the instruments measuring humidity.
Answer:
Hygrometer.

Question 21.
What is measured by a Six’s Maximum and Minimum thermometer?
Answer:
Maximum and minimum temperatures of a day.

Question 22.
On what does the amount of rainfall depend ?
Answer:
Moisture content of the air.

Question 23.
What is the side of the mountain facing away from the wind called?
Answer:
Leeward side.

Question 24.
Which is the most widespread form of rainfall ?
Answer:
Orographic or relief rainfall.

Question 25.
Where are the meeting of warm and cold fronts common ?
Answer:
The middle latitudes.

Question 26.
Which season receives most of the rainfall on the earth’s surface?
Answer:
Summer.

Question 27.
Do the borders or interiors of the continents get more rainfall ?
Answer:
Borders of the continents.

Question 28.
Which is the hottest part of the earth ?
Answer:
The equatorial region.

Question 29.
Among on-shore and off-shore winds, which one has less moisture content?
Answer:
Off-shore winds.

Question 30.
What happens to relative humidity when temperature decreases ?
Answer:
Relative humidity increases.

Detailed explanations in West Bengal Board Class 10 Geography Book Solutions Chapter 1.4 Works of Wind offer valuable context and analysis.

WBBSE Class 10 Geography Chapter 1.4 Question Answer – Works of Wind

Answer in short : 2 Marks

Question 1.
Name the areas where wind action is predominant.
Answer:
Wind action is predominant in :
(a) Desert regions (tropical and subtropical)
(b) Arid regions adjacent to deserts.
(c) Coastal regions.

Question 2.
On what factors does the erosive actions of wind depend ?
Answer:
Erosive action of wind depends on :
(a) Wind speed (b) Amount of sand, pebbles etc. carried by the wind, (c) Rock structure of the region (d) Vegetation cover (e) Heat, humidity and amount of rainfall.

Question 3.
Name some famous deserts of the world.
Answer:
Sahara of Africa, Atacama of Chile, Gobi of Mongolia, Soneran of North America etc.

Question 4.
What is a ventifact ?
Answer:
In deserts where wind blows from a single direction, large rocks standing in the path of the wind get polished on one side due to abrasion. This one side polished face with sharp edges is called a ventifact.

Question 5.
What is loess?
Answer:
Plains formed by deposition of fine sand particles carried by wind far away from the place where they belong, are called loess or loess plains.

Question 6.
What is a dreikanter?
Answer:

In deserts where winds blow from different directions in different seasons, the big rocks lying in the path of the wind get polished on all sides due to abrasion. This multi sided polished faced with sharp edges is called a dreikanter.

Question 7.
What is an oasis ?
Answer:
In a desert, when sand is deflated from an area continuously, creating a deep hollow or basin, the level of grand water may get exposed. Thus water may seep out from this place forming a shallow water body. This is known as an oasis. A few plants may grow here. A few settlements may also develop.

Question 8.
What is a playa?
Answer:
Shallow lakes created in depressions surrounded by hills in a desert region are called playa.

Question 9.
What is a bajada?
Answer:
The plain land developed adjacent to a pediment by deposition of eroded materials in a deserted region, is called a bajada.

Question 10.
What is a pediment?
Answer:
When high plateaus or mountains in desert areas are lowered by wind abrasion, the sloping stony plains formed at the foot of the mountain is called a pediment.

Question 11.
What are mesa and butte?
Answer:

‘Mesa’ means ‘table’ in Spanish. In desert areas, if plateaus are highly dissected by wind erosion, the flat topped landforms thus formed are called mesa. When mesa gets eroded and reduced in size, they are called butte.

Question 12.
What is a gour?
Answer:
Due to wind abrasion, when the lower parts of big rocks get more eroded than the higher parts, the feature thus formed resembles like a mushroom. This narrow based and broad-topped landform is called a gour.

Question 13.
What is a wadi?
Answer:
In desert regions, narrow river valleys created by rainwater are called wadis. They remain dry for most of the year.

Question 14.
What is a ‘dhand’?
Answer:
In Rajasthan, low depressions created by deflation of sand by wind in desert regions are called ‘dhand’.

Question 15.
Name the northernmost hot desert and the driest hot desert of the world.
Answer:
Northernmost hot desert – Gobi desert, Driest hot desert – Atacama desert of Chile.

Question 16.
What is the rate of average rainfall in the hot deserts of the world?
Answer :
Averge rainfall in the hot deserts of the world is around $25 \mathrm{~cm}$ per year.

Question 17.
What kind of ocean currents pass beside the deserts of the world ?
Answer:
Except for the deserts in Asia, all the other deserts of the diferent continents of the world have cold currents flowing beside them.

Question 18.
What is a ‘Blow-out’ ?
Answer:
In a desert, when tonnes of sand are blown away by winds, thus creating a hollow or depression which is quite deep, is called a ‘Blow-out’. This is an erosional feature found in a desert. Eg. – Katara in Egypt.

Question 19.
Which desert in the world has the largest moving sand dunes ?
Answer:
Rub-al-Khali desert of Saudi Arabia, Asia.

Question 20.
What is an inselberg ?
Answer:
In a desert, the rocky surfaces get reduced by abrasion and attrition of wind action. But, if a resistant rock is present in the path of the wind, it cannot be eroded and lowered equally with the surrounding rock surfaces. Hence, they stand out like isolated or island mountains within the deserts. These are called inselbergs.

Question 21.
What are Barkhans?
Answer:
The crescent shaped sand dunes created in perpendicular direction to the direction of wind in a desert, are called Barkhans. Eg. – Such crescent sand dunes can be seen in the Sahara and Kalahari deserts in Africa.

Question 22.
What are Seif dunes?
Answer:
Seif dunes are sand dunes produced in a desert lying parallel to the dirction of wind. They can be several kilometres long but only a few metres wide.

Question 23.
What is an erg ?
Answer:
The huge deserts formed only of sand particles are known as ergs in Sahara. The same landforms are known as kums in Turkistan. Eg.-Rub-at-khali in Saudi Arabia is the largest erg in the world.

Question 24.
What is reg?
Answer:
The deserts formed of rock fragments of various sizes are known as reg in Algeria.

Question 25.
What are sand dunes?
Answer:
The sand particles moved by wind action in a desert and dumped in huge heaps are called sand dunes.

Question 26.
What is a desert pavement?
Answer:
A desert region composed of unequal pieces of rock fragments is called desert pavement.

Answer briefly : 3 Marks

Question 1.
What are the reasons for predominant wind action in arid regions?
Answer:
Although wind blows over the whole of the earth, its action is predominant in arid regions. This is because :

1. No obstacle in wind direction : In desert regions, due to lack of rainfall, there is no or very less vegetation cover. Thus wind blows unhindered with high speed.
2. Loose and exposed soil : Lack of vegetation makes the soil loose and exposed to wind action.
3. High diurnal range of temperature : Great difference between day and night temperature causes rocks to crack and break due to contraction and expansion. This makes the work of the wind easier.

Question 2.
What are the different methods of wind erosion?
Answer:
The different methods by which the wind erodes are:

1. Deflation : This refers to the process of remaining unsorted dust and sand particles by blowing out by winds.
2. Abrasion : By this method, the sand and rock particles carried by the wind rub, scour, groove, cut and polish any rock surface that comes in its way.
3. Attrition : By this method, the rock and sand particles carried by the wind strike against each other, break and reduce in size.

Question 3.
Differentiate between Yardang and Zeugen.
Answer:

Question 4.
Mention the factors on which the erosive power of wind depends.
Answer:
The erosive power of wind depends on – (i) Wind speed (ii) Amount and nature of sand, pebbles and rock fragments carried by the wind (iii) Nature of rock beds (iv) Vegetation cover (v) Heat, humidity and amount of rainfall.

Question 5.
What is a pediment ?
Answer:
When high plateaus or mountains in deserts are highly eroded and lowered by wind abrasion, the sloping stony plains formed at the foot of the mountains is called a pediment.

Question 6.
Differentiate between a Pediment and a Bajada.
Answer:

Pediment	Bajada
i. Formed by combined work of wind and water at the foot of the mountains due to erosion.	i. Formed by combined action of wind and water by deposition of sand, clay, pebbles etc.
ii. Lies at the foot of mountains highlands in deserts.	(ii) Lies in the stretch between a pediment and playa in a desert.
iii. It is a hard rocky region.	iii. It is formed by deposition of loose materials like sand, pebbles, gravels etc.
iv. Pediments are slightly concave in shape.	iv. Bajada are slightly convex and look something like alluvial cones.

Question 7.
What is a blow-out?
Answer:

The basins or hollows which are formed by sweeping away of loose, light and sandy particles by winds, are called blow-outs or deflation basins. They are known as ‘dhand’ in Rajasthan. The largest blow-out of the world is the Qattara depression in Egypt.

Question 8.
Differentiate between barkhans and seif dunes.
Answer:

Question 9.
What is loess plain ?
Answer:
An yellowish sediment produced by wind-blown silt deposition, usually in the size range of 20-50 micrometer, loosly cemented by calcium carbonate is called loess. The flat regions covered by such deposits are called loess plains. This helps to make farm land very fertile.

Question 10.
Why wind action also active in the coastal regions ?
Answer:
Action of wind is very active in desert area. But it is also active in coastal area, because :
1 . Open and extensive coastline helps to blow the sea breeze towards the land with no obstraction and cause erosion of coastal area.
2. Sea waves are help to break the rocks of coastal area into small granules which can be then easily blow away by the wind.
3. Uninterrupted wind blown through the coastal area carried sand prevent in the coast and formed landforms like sand dunes in the coastal region.

Question 11.
What is an Inselberg ?
Answer:

The German term inselberg means ‘Island mountain’. They are outstanding, rounded, steep-sided residual hills rising abruptly from nearby eroded flat surface. Their height may vary from 10-300 m.

Question 12.
Name the landforms formed by combined action of wind and water.
Answer:
Landforms formed by combined action of wind and water are : wadi, playa, pediment and bajada.

Question 13.
Name the regions where wind action is predominant in creation of new landforms.
Answer:
The regions where wind action is predominant in creation of new landforms are:

1. Deserts (Tropical and sub-tropical regions)
2. Semi-arid and dry regions adjacent to deserts.
3. Coastal areas.

Question 14.
How is sand particles formed in desert regions ?
Answer:
In deserts, due to high temperature fluctuations between day and night, the barren exposed rocks are severely expanded and contracted regularly. This causes breaking of the rocks into smaller parts and finally leads to the formation of sand. The pebbles and fragments of rocks borne by the wind hit against the rocky walls of mountains, hills or other land surfaces. This causes high rates of erosion, and thus leads to formation of sand. Presence of hard minerals in the broken rock fragments cause exploding action when they colide with the rock surfaces. This also helps in creation of sand.

Answer in details : 5 Marks

Question 1.
Name and describe the landforms formed by wind depostion.
Answer:
The different landforms formed by wind deposition are :
(i) Longitudinal or Seif dunes : Low but long ridges of sand particles lying parallel to the wind direction are called seif dunes. They may be 40-70 m. in height, about 100 m in width, and a few kilometres in length.

(ii) Transverse dunes: When dunes are formed perpendicular or transversely to the wind direction, they are called transverse dunes. They are common in deserts where sand supply is abundant and wind speed is moderate.

(iii) Barkhans : Crescentshaped sand dunes that receive wind from only one direction are called barkhans. They have two horns opposite to the wind direction.
(iv) Loess : Fine sand particles, carried by winds and deposited far away from their place of origin, forming extensive plants are called loess.

Question 2.
What are the main causes of spread of deserts or desertification?
Answer:
The main causes of desertification are :
(a) Physical causes :

1. Drought : Regular and repeated droughts may damage the soil permanently, preventing any vegetative growth, hence bringing in desertification.
2. Climatic changes : Green house effect and global warming may affect the climate of an area and advance desertification.
3. Soil erosion : Removal of top soil may also cause desertification.
4. Presence of mountains : Presence of mountains may obstruct moisture-laden winds to cause rainfall. Hence deserts may be created in the rain shadow areas.

(b) Man-made causes :

1. Over-grazing : Over-grazing may remove the vegetative cover of the soil permanently, and cause desertification.
2. Over-cultivation : Unscientific cultivation may cause removal of nutrients from the soil and cause further extension of deserts.
3. Uncontrolled irrigation : Over-irrigation may cause soils to become saline, loose fertility and tend to turn into deserts.
4. Deforestation : Cutting down of trees remove vegetative cover and cause desertification.

Question 3.
What are the methods of controlling desertification?
Answer:
The process of desertification is very difficult to stop totally. But certain steps may be taken for its control :

1. Controlled grazing : Grazing should be controlled, especially in arid and semiarid regions.
2. Cultivation : Cultivation of drought resistant crops must be encouraged near deserts.
3. Afforestation : Trees should be planted to cover up exposed areas.
4. Irrigation : Controlled irrigation helps to improve soil quality.
5. Others : Other steps that can be taken are – rain water harvesting, preventing salinity of soil, proper planning of land use, increasing consciousness among people etc.

Question 4.
What are the causes of desertification of Sahara? What are the remedial steps taken?
Answer:
Sahara in Africa is the largest hot desert of the world, covering about 91,00,000 sq km area.
Causes of desertification : (i) Extreme sand storms (ii) Lack of rainfall due to global warming (iii) Reduction of agriculture at the borders of the desert.

Preventive measures :

1. The Federal state and the govt. of Nigeria has taken up annual tree planting programmes. Free plants are distributed to be planted in agricultural fields and houses.
2. Heavy reforestation programmes are taken up in dry areas of Mali, Mauritania, Niger, Sudan, Senegal, Chad, Ethiopia etc.
3. Involvement of ladies, youth and students in reforestation and awareness programmes.

Question 5.
Mention the causes of spread of the Thar desert and the preventive measures taken.
Answer:
The Thar desert spreads over 2.34 million sq. km. in India over west Rajasthan, Gujarat, south west Punjab and parts of Haryana.

Causes of spread of desert : (i) High speed winds (ii) Large moving sand dunes (iii) High diurnal range of temperature (iv) Low rainfall (v) High rate of evaporation.
Preventive measures : (i) Reforestation is being done on the hill slopes in this region according to several government programmes. (ii) Artifical grasslands are being created to prevent movement of sand dunes in Barmer, Jaisalmer, etc. (iii) Trees that grow fast, are being planted to meet the demand of fuel wood of local people in Jaisalmer, Jhuijhunu etc.(iv) The Rajasthan canal has been constructed to irrigate and reclaim infertile land.

Question 6.
Name and describe three landforms created by erosive action of wind.
Answer:
The landforms created by erosive action of wind are :

(i) Gour : When the lower portions of a huge rock mass is eroded away much more compared to the upper portions, the landform thus formed resembles a mushroom. Such top heavy features are called ‘Gour’.
(ii) Yardang : When hard and soft rocks lie in bands in vertical direction to the direction of the wind the softer rocks get eroded very fast, while the harder rocks act like resistances and get less eroded. The harder rocks have rugged surfaces. These are called ‘Yardangs’.

(iii) Zeugen : When hard and soft rocks lie in bands perpendicular to the direction of wind, the soft rocks are eroded away very fast. The hard rocks stand out like broad topped and narrow-based landforms. These are called ‘Zeugens’.

Question 7.
Describe the different landforms formed by combined action of wind and water in desert areas.
Answer:
The different landforms formed by the combined action of water and wind in a desert region are :
(i) Wadi : In deserts sudden torrential rains lead to formation of valleys through which the collected rain water may flow like a river. In dry season, these valleys also remain dry.

(ii) Playa : Playas are small lakes found in deserts. They are highly saline and the water cannot be used for agricultural or household purposes.
(iii) Pediment : Pediment refers to the eroded and lowered plainlands that lie at the foot of the mountains.

(iv) Bajada : Bajada refers to the deposition of materials, brought down by wind as well as water and deposited beyond the pediment.

Multiple Choice Question (MCQ) : 1 Mark

Question 1.
Loess is commonly formed by deposition of
(A) Silt by wind
(B) Sand by wind
(C) Silt by rivers
(D) Dust by volcanoes
Answer:
(B) Sand by wind

Question 2.
The crescent shaped sand dunes are called
(A) Barkhans
(B) Seif
(C) Yardang
(D) Arete
Answer:
(A) Barkhans

Question 3.
Landforms, not associated with wind erosion is
(A) Rock pedestal
(B) Zeugen
(C) Yardang
(D) Dunes
Answer:
(D) Dunes

Question 4.
Pediments are formed in
(A) Arid regions
(B) Coastal regions
(C) Glacial regions
(D) Valley regions
Answer:
(A) Arid regions

Question 5.
Gour can be found in
(A) Coastal area.
(B) Arid region
(C) Glaciated region
(D) Island area
Answer:
(B) Arid region

Question 6.
Lakes formed within sand dunes are called
(A) Dhands
(B) Dhrians
(C) Playas
(D) Shots
Answer:
(A) Dhands

Question 7.
Wadis are
(A) Mountain Valley
(B) Flower Valley
(C) Depressional Valley
(D) Dry Valley
Answer:
(D) Dry Valley

Question 8.
Bajada is a
(A) Erosional plain formed by wind
(B) Depositional plain formed by wind and water
(C) Erosional plain formed by river
(D) Depositional plains formed by glaciers
Answer:
(B) Depositional plain formed by wind and water

Question 9.
Yardang is formed by
(A) Glacial deposition
(B) Marine deposition
(C) Wind erosion
(D) Sea erosion
Answer:
(C) Wind erosion

Question 10.
Isolated hard resistant rocks scatterd in plain deserts are called
(A) Monadnocks
(B) Inselbergs
(C) Drumlins
(D) Spur
Answer:
(B) Inselbergs

Question 11.
The steep-sided, deeply undercut, overhanging rock ridges separated from one another by long grooves in desert floors of relatively softer rocks are called
(A) Dreikanters
(B) Ventifacts
(C) Zeugens
(D) Yardangs
Answer:
(D) Yardangs

Question 12.
Wind windows and window bridges are ______ land forms.
(A) Transportational
(B) Erosion
(C) Depositional
(D) None of these
Answer:
(B) Erosion

Question 13.
Accumulation of sands between obstacles are called
(A) Sand shadows
(B) Sand drifts
(C) Sand dunes
(D) Ripple marks
Answer:
(B) Sand drifts

Question 14.
The wind-borne materials deposited beyond the limits of the deserts by wind action are called
(A) Sand dunes
(B) Loess
(C) Ripple marks
(D) Barkhans
Answer:
(B) Loess

Question 15.
The loess formation in China is most prominent in
(A) North China
(B) East China
(C) South China
(D) West China
Answer:
(A) North China

Question 16.
Wind erosion in the arid and semi-arid regions is assisted by
(A) Chemical weathering
(B) Mechanical weathering
(C) Biological weathering
(D) Differential weathering
Answer:
(B) Mechanical weathering

Question 17.
Wind erosion is largely controlled and determined by
(A) Wind velocity
(B) Compositions of rocks
(C) Nature of Vegetation
(D) All of these
Answer:
(D) All of these

Question 18.
The process of removing, lifting and blowing away dry and loose particles of sads and dusts by wind is called
(A) Deflation
(B) Abrasion
(C) Attrition
(D) Corrosion
Answer:
(A) Deflation

Question 19.
Which of the following rocks are called ‘gara’ in Sahara?
(A) Dreikanter
(B) Dunes
(C) Stone lattice
(D) Mushroom rocks
Answer:
(D) Mushroom rocks

Question 20.
Wind transports materials by the process of
(A) Suspension
(B) Saltation
(C) Traction
(D) All of these
Answer:
(D) All of these

Question 21.
The mineral abundantly found in sand duhes is
(A) Quartz
(B) Kaolin clay
(C) Feldspar
(D) Clay
Answer:
(A) Quartz

Question 22.
The dunes formed along coasts and margins of deserts are called
(A) Longitudinal dunes
(B) Transverse dunes
(C) Bankhan dunes
(D) Parabolic dunes
Answer:
(B) Transverse dunes

Question 23.
The sand dunes formed parallel to wind direction are called
(A) Transverse dunes
(B) Barkhan dunes
(C) Parabolic dunes
(D) Longitudinal dunes
Answer:
(D) Longitudinal dunes

Question 24.
Which of the sand dunes have two horns ?
(A) Nebkha
(B) Barkhan
(C) Seif
(D) Transverse dunes
Answer:
(B) Barkhan

Question 25.
The example of the most significant wind blown deposits is
(A) Sand dunes
(B) Loess
(C) Ripple marks
(D) Playa
Answer:
(B) Loess

Question 26.
Loess is known as ‘Limon’ in
(A) France
(B) Nebraska
(C) Australia
(D) China
Answer:
(A) France

Question 27.
‘Inselberg’ was first named by
(A) W. M. Davis
(B) L. C. King
(C) R. L. Parker
(D) R. A. Bagnold
Answer:
(B) L. C. King

Question 28.
Seif dunes were first named by
(A) L.C.King
(B) W. Penck
(C) W. M. Davis
(D) R. A. Bagnold
Answer:
(D) R. A. Bagnold

Question 29.
The dry river channels in arid regions are called
(A) Wadi
(B) Bolson
(C) Salina
(D) Loess
Answer:
(A) Wadi

Question 30.
The salt lakes found in arid regions are called
(A) Bolson
(B) Wadi
(C) Playa
(D) Dhand
Answer:
(C) Playa

Question 31.
The shifting dunes of Rajasthan are locally known as
(A) Dhrian
(B) Barchan
(C) Loess
(D) Blow out
Answer:
(A) Dhrian

Question 32.
Cresentic dunes are called
(A) Seif
(B) Barchan
(C) Loess
(D) Blow out
Answer:
(B) Barchan

Question 33.
Pediments are formed by the ______ works of wind and temporary stream.
(A) Erosional
(B) Transportational
(C) Depositional
(D) Erosional and Depositional
Answer:
(A) Erosional

Question 34.
The hard rocks standing like dames or hills is a desert are called
(A) Mushroom rock
(B) Inselbergs
(C) Yardangs
(D) Bajada
Answer:
(B) Inselbergs

Question 35.
‘Gara’ is formed by the action of
(A) River
(B) Glacier
(C) Wind
(D) Waves
Answer:
(C) Wind

Question 36.
Barchans get gradually converted to
(A) Akle dunes
(B) Seif
(C) Gara
(D) Wadi
Answer:
(B) Seif

Question 37.
Marusthali means
(A) Land of the dead
(B) Rainshadow region
(C) A land of heavy rainfall
(D) Lack of camels.
Answer:
(A) Land of the dead

Question 38.
Mesas are eroded further to form
(A) Zeugen
(B) Butle
(C) Inselberg
(D) Yardang
Answer:
(B) Butle

Question 39.
The dome shaped low hills present is the peneplain regions are called-
(A) Monad rocks
(B) Gara
(C) Yardang
(D) Till
Answer:
(A) Monad rocks

Question 40.
In peneplain, low lying hill of hard rocks remains as residual landform is called
(A) Yardang
(B) Zeugen
(C) Sand dunes
(D) Inselberg
Answer:
(D) Inselberg

Fill in the blanks : 1 Mark

1. The playa lakes in the arid regions of Africa are known as _______.
2. The playa lakes in the desert region of Rajasthan are known as _______.
3. The crescent-shaped sand dunes lying perpendicular to the wind direction are called _______.
4. The vast sandy deserts in Sahara, lacking any vegetation are called _______.
5. The playa lakes are known as _______ in the desert regions of Mexico.
6. _________ is the largest sandy desert of the world.
7. _________ dunes are created from seif dunes.
8. The desert research centre of India is located at _______.
9. The term ‘dreikanter’ means _______.
10. _______ is a cold desert in India.
11. Loess comes from a German word meaning _______.
12. _______ has its origin in the Arabic word meaning ‘Sword’.
13. Thick loess deposits are found in _________ in India.
14. The desert lakes in Sahara are known as _______.
15. Oases are formed by ________ action of wind.
Answer:
1. Shots
2. Dhand
3. Barkhans
4. Erg
5. Bolson
6. Rub-at-khali desert in Saudi Arabia
7. Barkhan
8. Jodhpur
9. Three-sided
10. Ladakh
11. Loose materials
12. Seif
13. M.P.
14. Shalts
15. Erosion

State True or False : 1 Mark

1. Barkhans mean crescent-shaped dunes. [ ]
2. The largest desert of the world is Sahara. [ ]
3. The action fo wind is mostly noticed in high mountains [ ]
4. Barkhans are formed by erosional action of winds. [ ]
5. The sand dunes along the coastal region of Kerala are called terres. [ ]
6. The largest deflation hollow of the world is Qatara. [ ]
7. The driest desert of the world is Sahara. [ ]
8. The rocky part of the Sahara desert is called hamada. [ ]
9. The region between two seif dunes is called gasi. [ ]
10. Oases are created due to abrasion of wind. [ ]
11. Pediment is a type of plain. [ ]
12. The loward slope of the ventifact is smooth and sharp. [ ]
13. The landforms looking like mushrooms found in deserts are called yardang. [ ]
14. The Salt water lakes of deserts are called wadies. [ ]
15. The Taklamakan Desert lies in China. [ ]
16. ‘Mesa’ means ‘Chair’ in Spanish. [ ]
Answer:
1. True
2. True
3. False
4. False
5. True
6. True
7. False
8. True
9. True
10. True
11. True
12. False
13. False
14. False
15. True
16. False

Match the following :

List 1	List 2
A. Sahara	i. Asia
B. Gobi	ii. Africa
C. Salina	iii. South America
D. Barkhan	iv. North America
E. Soneran	v. Kirghiz, Steppe region
F. Atacama	vi. Playa lake

Answer:

List 1	List 2
A. Sahara	ii. Africa
B. Gobi	i. Asia
C. Salina	vi. Playa lake
D. Barkhan	v. Kirghiz, Steppe region
E. Soneran	iv. North America
F. Atacama	iii. South America

Answer in few words : 1 Mark

Question 1.
What are sandy deserts known as ?
Answer:
Erg.

Question 2.
What are the moving sand dunes of Rajasthan called ?
Answer:
Dhrians.

Question 3.
What are rocky deserts known as ?
Answer:
Hamada.

Question 4.
What are ‘gours’ also known as ?
Answer:
Gara, or mushroom rocks or rock pedestals.

Question 5.
What are inselbergs?
Answer:
Outstanding rounded steep-sided residual rocks or hills in deserts.

Question 6.
What are deflation basins ?
Answer:
Hollows created in deserts by sweeping away or deflation of sand by wind.

Question 7.
What are dunes?
Answer:
Heaps of sand formed by wind deposition in deserts.

Question 8.
What are Barkhans?
Answer:
Crescent shaped sand dunes.

Question 9.
Which is the largest ‘hot’ desert of the world ?
Answer:
Sahara desert in Africa.

Question 10.
Where does the Thar desert lie in India ?
Answer:
West Rajasthan, Gujarat, South-western Punjab and parts of Haryana.

Practicing with West Bengal Board Class 10 Geography Book Solutions and West Bengal Board Class 10 Geography Question Paper 2020 alongside detailed explanations can lead to a deeper understanding of the subject.

WBBSE Class 10 Geography Question Paper 2020

Group-A.

1. Write the correct answer from the given alternatives: 1×14=14

Question 1.
The process by which, soil and rock layers move down along the slope of highlands by gravity is called:
a. Weathering
b. Gradation process
c. Endogenic processes
d. Mass wasting process
Answer:
d. Mass wasting process

Question 2.
In pediplain, low lying hills of hard rocks remain as residual landform is called :
a. Yardang
b. Zeugen
c. Sand dunes
d. Inselberg
Answer:
d. Inselberg

Question 3.
“Horse Latitude” is located at :
a. Equatorial low pressure belt
b. Sub-tropical high pressure belt
c. Sub-polar low pressure belt
d. Polar high pressure belt
Answer:
b. Sub-tropical high pressure belt

Question 4.
Diurnal range of temperature is maximum in :
a. Equatorial climatic region
b. Hot desert climatic region
c. Tropical Monsoon climatic region
d. Mediterranean climatic region
Answer:
b. Hot desert climatic region

Question 5.
The formation of ocean currents depend on :
a. Prevailing winds
b. Earth’s revolution
c. Sand banks
d. All of them are applicable
Answer:
a. Prevailing winds

Question 6.
The time difference between high and low tides at a place is nearly :
a. more than two hours
b. more than six hours
c. more than four hours
d. more than eight hours
Answer:
b. more than six hours

Question 7.
Carbon particles emitted by vehicles are controlled by use of :
a. Cyclone Separators
b. Electrostatic Precipitator
c. Scrubber
d. Coated Alumina
Answer:
c. Scrubber

Question 8.
Parallel of latitude, passing through the middle of India is :
a. Equator
b. Tropic of Capricorn
c. Prime Meridian
d. Tropic of Cancer
Answer:
d. Tropic of Cancer

Question 9.
The lake located, in between the deltas of Godavari and Krishna rivers is :
a. Kolleru
b. Pulicat
c. Chilka
d. Vembanad
Answer:
a. Kolleru

Question 10.
The most extensive method of irrigation, practiced in India is :
a. Wells and tube wells
b. Tanks
c. Canals
d. Sprinkler
Answer:
a. Wells and tube wells

Question 11.
Western disturbances occur in India during :
a. Summer season
b. Autumn season
c. Rainy season
d. Winter season
Answer:
d. Winter season

Question 12.
Salty sea breeze is needed for :
a. Sugar cultivation
b. Tea cultivation
c. Jute cultivation
d. Coffee cultivation
Answer:
a. Sugar cultivation

Question 13.
Petro-chemical industrial centre of West Bengal is located at :
a. Junput
b. Kolkata
c. Sankarpur
d. Haldia
Answer:
d. Haldia

Question 14.
The colour used for drawing of contour lines in topographical map is :
a. Brown
b. Black
c. Red
d. Blue
Answer:
a. Brown

Group-B.

1. If the statement is true, write ‘T’ and if false, write ‘F’ against the following answer any six: 1×6=6

1. The confluence of Alakananda and Bhagirathi rivers is at Devprayag.
Answer: True

2. Mistral is a warm local wind which blows over Rhone valley in France.
Answer: False

3. Floods occur in India in the years of El-Nino.
Answer: False

4. The position of sun, moon and earth along a straight line is known as syzygy.
Answer: True

5. Papers may be manufactured by recycling newspapers as raw material.
Answer: True

6. The soil composed of pebbles, sands and silts, found along the foothills of Siwalik is called bet.
Answer: False

7. For analysis of satellite imageries, use of computer is mandatory.
Answer: True

2. Fill in the blanks with suitable words answer any six: 1×6=6

1. The process of modifying landforms by combined action of erosion and weathering is called ……..
Answer: Gradation

2. Oases are formed by ………………… action of wind.
Answer: Erosional/Deflational/Blouring

3. With the increase of air pressure gradient, wind velocity ………..
Answer: Increases

4. The cold ocean water from polar region flows as ………………… current towards equator.
Answer: Cold

5 The longest national highway of India is NH …………..
Answer: 44

6. Indian Space Research Centre is situated at …………..
Answer: Thiruvananthapuram

7. In short, electronic waste is known as ………….. waste.
Answer: e

3. Answer in one or two words answer any six: 1×6=6

1. Name the largest valley glacier of the world.
2 Where in the atmosphere over the earth surface ozone hole was first discovered?
3 Name the southern-most mountain pass of Western Ghats.
4 What is the local name of the lagoons in Kerala coast?
5 Name the highest waterfall of India.
6 In which city of India underground rail first started its journey?
7 Which is the most populous state of India?
8 In what form the satellite imagery is produced?
Answer:
1. Lambert glacier in Antarctica.
2. Antarctica
3. Pal ghat (Palakkad gap)
4. Kayal
5. Kunchikal waterfalls of karnataka
6. Kolkata
7. Uttar Pradesh
8. Digital form

4. Match the Left Column with the Right Column:1×4=4

A	B
1. Ratna	a. Pine
2. Coniferous forest	b. Murmagaon
3. Railway coach manufacturing centre	c. High-yielding variety rice seed
4. Iron ore exporting port	d. Perambur

Answer:
1-c, 2-a , 3-d, 4 -b

Group-C.

3. Answer the inflowing in brief (Alternatives should be noted): 2×6=12

Question 1.
What is Plunge Pool?
OR Define Loess.
Answer:
The depression or hole created at the foot of a waterfall due to falling or plunging of water along with rock fragments with high velocity, is known as a plunge pool.

OR.
Plains formed by deposition of fine sand particles carried by wind far away from the place where they belong, are called loess or loess plains. Eg-A loess plain has been formed along the valley of river Hwang Ho in China, due to deposition of sand blows away from the gobi desert.

Question 2.
What is relative humidity?
OR, What do you mean by Perigean tide?
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 of water vapour that the air can hold at that particular temperature, is known as relative humidity. It is expressed as a percentage.

Relative humidity
\(=\frac{\text { Actual amount of water vapour present in air }}{\text { Maximum amount of water vapour the air can hold at that temperature }} \times 100\)
Or
\(\text { Relative humidity }=\frac{\text { Absolute humidity }}{\text { Humidity capacity }} \times 100\)
Or
A perigean tide occurs when the moon comes closest to the earth (on a new moon or full moon day) while revolving around the earth on its orbit. The strongest perigean tide occurs three or four times a year when a perigee (nearest position of the moon to the earth) coincides with a spring tide (When the sun, the moon and the earth are nearly aligned in every two weeks).

Question 3.
What is a landfill in waste management?
OR
Define municipal wastes.
Answer:
The method of discarding wastes in approved grounds, filling up the huge holes dug to bury the wastes callected, is called land-filling. Land-filling 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 requires a large vacant land and produces strong methane and other gases, and cause contamination problems.
OR.
The wastes generated in the urban areas, or municipal areas. are known as municipal wastes. These include trash of garbage from households, schools, offices, markets, restaurants and other public places; obsolute computers, mobiles and other electronic goods; furniture and old fashioned clothes etc.

Question 4.
Mention two characteristic features of desert vegetation in India.
OR.
What do you mean by “Dun”?
Answer:
Characteristics of desert vegetation in India are :

• It is found in Rajasthan, Kachch and Kthiawar Peninsular region of gujarat and the rain shadow area of Decan Plateau.
• The vegetation is very sparsely spread.
• The leaves of the plants are reduced to thorns due to lack of water. The roots are very long to absorb underground water. The stems are flashy and have a waxy coating over them.

OR.
The valleys lying in the siwalik range are called ‘Duns’ or ‘Doons’. The Siwalik range has been formed much later than the Himadri and Himachal Himalayas. During the formation of the siwalk, the rivers that were flowing ran the higher Himalyan ranges got interupted 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 5.
Define ancillary industry.
OR
Name the two terminal centres of the longest inland waterways in India.
Answer:
The industries which supply their finished products as raw materials for some other industries or support the growth of other industries are called basic industries, and the industries which receive these raw materials or are supported by these basic industries, are called ancillary industries. Eg-Ancillary industries for the automobile industry are-tyre industry battery industry, glass industry etc.
OR.
The longest inland waterway of india (also called National Waterway 1) lies along the Ganga-Bhagirathi-Hooghl river system. It is 1,620 km long, lying between Prayagraj in Allahabad in the north to Haldia in West Bengal (Sagar) in the south.

Question 6.
What do you mean by sensor?
OR.
State two uses of topographical maps.
Answer:
A sensor is a specialised camera that is installed in a satellite in order to take photographs of the earth. It can be of two types. An active sensor uses its own energy for illumination and helps the satellite to capture images at night. A passive sensor can help the satellite to capture images only when the sun is illuminating the earth.
OR.
The uses of topographical maps are :

• It helps to understand and study the physical characteristics of the region.
• It helps to understand and analyse the different cultural features (roads, settlements, etc.) of the same area with respect to the physical features present there.
• It helps to analyse the relation between man and nature, and helps to plan for economic development.

Group-D.

Give brief explanatory answer (Alternatives should be noted):-

Question 1.
Discuss in brief about three processes of river transportational activity.
OR.
Mention the relationship between Jet stream and Indian Monsoon system.
Answer:
The river transports its load by the following processes:

• Traction: The heavier and large rock fragments are forced to flow down along the river water by rolling on the floor of the river channel due to gravity.
• Saltation: The comparatively smaller fragments of rocks are moved downstream by jumping over the floor of the river channel along with the water continuously.
• Suspension: The fine particles of the river’s load remain suspended in the river due to buoyancy of water, while they are carried downstream.
• Solution: The soluble particles are dissolved in the river water and moved downstream.

OR.
Jet stream is a thin stream of speedy winds (350-450 km/hr) that blow from west to east from the winter till March-April between the Troposphere and the Stratosphere. These winds play an important role in the Indian monsoon system. These winds influence the onset and retreat of the monsoons in India, by seasonal shifting and creation of low presure and high presure calls respectively.

Question 2.
Classify wastes according to nature along with examples.
OR.
State three necessities of waste management.
Answer:
The different types of wastes are :

• Solid wastes: Solid wastes are any type of garbage or rubbish generated at home or outside. Eg-Food wastes newspaper, broken household or office articles, etc.
• Liquid wastes: Liquid wastes include wash waters from homes, cleaning liquids used in industries, waste waters or liquids from industries, etc. Sometimes, solid wastes are converted to liquids before discarding.
• Gaseous wastes: Gaseous wastes include CO₂, SO₂, N₂O NH₃ etc. produced as a result of manufacturing activities in industries comsumption of differnent products and other biological processes.
• Toxic wastes : Toxic wastes are harmful and hazardous poisonous wastes that threaten public health and environment. Eg-pesticides, mercury, containing equipments, lamps, batteries, etc.
• 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. Eg-domestic wastes, food left-overs, paper, glass, etc.

OR.
The necessities of proper waste management system are-

• To control different types of pollution.
• To control the spread of infectious diseases.
• To conserve environmental resources like forests, minerals, water etc.
• To reduce the amount of wastes generated everyday.
• To recycle hazardous wastes for further production of useful items.

Question 3.
Discuss three advantages each of roadways and railways in India.
OR.
State the merits of agricultural revolution as experienced in the States of Punjab and Haryana.
Answer:
The advantages of roadways in India are as follows :

• The light weight and less bulky commodity can be easily transported from one corner of the country to the other.
• A variety of vehicles, eg-buses, trucks, cycles, auto rickshaws, vans, etc. can use the same road and carry different types of commodities and number of passengers and render door-to-door services as well.
• This is the easiest mode of transport for moving raw materials to factories and finished products to markets. Hence, a large percentage of economic development of the country depends upon the roadways.

The advantages of railways in India are as follows :

• Railways transport a huge quantity of goods and passengers at a high speed and at a low cost throughout the country.
• Railways carry seeds, fertilizers, agricultural equipments to the fields and the produced crops to the markets. Railways also transport minerals, power resources, equipments etc. to the industries and their finished products to the markets. Thus railways help to bring about agricultural and industrial development in India.
• Railways help in defence of the country by transporting soldiers, ration, war equipments and other necessary things to the border regions.

OR.
The agricultural revolution experienced in the States of Punjab and Haryana is popularly known as the Green Revolution. The merits of Green Revolution are-

• Remarkable increase on production of foodcrops, especially wheat.
• Extension of agricultural land.
• Modernisation and mechanisation of agriculture.
• Reduction of past attacks due to use of better quality of insecticides and pesticides.
• Employment and improvement in the economic condition of the farmers, and thus a rise in their standard of living.
• Reduction in import of foodgrains and huge increase in the export of the same.

Question 4.
Give an account of different types of scales in tabular form as used “topographical maps”.
OR.
Distinguish between Geostationary and Sun-Synchronous satellites.
Answer:
The different types of scales used in topographical maps areas follows :

OR

Geostationary Satellites
i. The artificial satellites that orbit the earth from west to east in circular orbits in the same time as that of earth’s rotation ( 24 hours), are called geostationary satellites.	i. The sun-synchronous satellites are those which are installed on a geocentric orbit that combines altitude and inclination in such a way, that the satellite passes over any given point of the planets surface at the same local solar time.
ii. They are installed at a height of of 36,000 km approximately, above the equator.	ii. They are installed at 700-800km above the land surface and orbit the earth in circular or elliptical paths from the north polar to south polar regions.
eg : GOES-E, GOES-W, etc.	iii. eg : IRS, LANDSAT, etc.

Group-E.

(Sketches are not essential for Sightless Candidates)

1. Answer any two questions from the following :

Question 1.
Describe with sketches three landforms carved out by glacial erosion.
Answer:
The landforms curved out by glacial erosion are as follows:

i. Cirque: At the source of the glacier, the mountain wall is heavily eroded by the process of plucking and abrasion. This it looks like a scooped out huge arm chair. This is known as a cirque or a corrie. Acrque may be filled with glacier melt water and may form a cirque lake or a corrie lake.

ii. Arete: In a show-covered mountains region, two or more glaciers may originate from different slopes of the same mountain. Thus, two or more cirques may be formed or the same mountain adjecent to each other. The steep and sharp wall that separates two adjecent cirques, is known as the arete.

iii. Pyramidal peak: If a mountain has three or more aretes, it takes the structure of a pyramid, and thus is called the pyramidal peak. The tip of such a peak becomes very sharp and pointed, and is called a horn.

iv. U-shaped valley : While the glacier flows down, the intensity of side erosion is same as that of vertical or down erosion by the processes of plucking and abrasion. Hence the valley developed looks like the letter ‘U’. Thus they are called U-shaped valley.

v. Hanging valley : In a glaciated region, the main or trunk glacier cames a greater volume of ice than the tributary glaciers. Thus the main glacier has more erosive power than the smaller tributary glaciers. Hence, the main glacier forms deper valleys and the tributary glaciers form comparatively less deeper valleys. These are not visible as long as the ice cover reviews found to be hanging over the huge deep valleys. Such valleys are called hanging valley.

Question 2.
Give an account of atmospheric layers of troposphere and stratosphere.
Answer:
Troposphere

• The lowest layer of the atmosphere, lying closest to the earth is known as Troposphere.
• It extends upto 18km near the equator and 18km near the poles.
• Temperature in this layer decreases by this is known as Lapse Rate.
• About three-fourths of the total mass of the atmosphere is concentrated in this layer.
• All the weather phenomena, like wind, rainfall, storm, etc, occur in this layer.
• The upper limit of the Troposphere is known as the Tropopouse.

Stratosphere

• Stratosphere is the second layer of the atmosphere that lies above the Troposphere.
• It spreads upto 50km above the earth’s surface.
• Temperature goes on increasing in this layer at the rate of 4 for every 50km.
• A huge concentration of ozone gas is found in this layer between 20-40 km. This is also known as the Ozonosphere.
• There is very less atmospheric disturbances here. A thin layer of cirrus clouds may form at the lower layers of the stratosphere.
• Jet planes fly through this layer due to less friction due to lack of air.
• The upper limit of the stratosphere is known as stratopause.

Question 3.
Mention the location of Mediterranean climatic region and discuss its major climatic characteristics.
Answer:
Mediteranean climate is found between 30°c – 40°c latitudes in both Northern and Southern hemispheres.

• Europe: Portugal, spain, Italy, Greece
• Aisa: Western Turkey, Lebanon, Syria, Israel.
• Africa: Egypt, Morocco, Northern Algeria, Cape town.
• North America: Southern California.
• South America: Chile
• Oceania: Southern and south-western coast of Australia.

Characteristics of Mediterranean climate

• Temperature remains moderate throughout the year.
• Average summer temperature lies between 14°c 22°c
• Average winter temperature lies between 10°c -14°c
• Summers are dry and the sky remains clear during this season.
• Most of the rainfall occurs during winter.
• Average annual rainfall is 35-75cm

Question 4.
Discuss the influences of ocean currents on global climate.
Answer:
The influences of ocean currents on global climate are :
i. Control on temperature: The warm currents move towards the polar regions from the equatorial region and the cold currents flow towards the equatorial region from the polar regions. This helps in maintaining a balance between temperature of various regions due to exchange of heat.

ii. Rainfall and snowfall: The regions along which warm currents flow experience heavy rainfall. The regions along which cold currents flow, are more prone to snowfall.

iii. El Nino and La Nina: During El Nino, a warm current flows from the north towards the coast of Peru and Ecuador in South America. This causes heavy rainfall in those regions. However, India and Australia may face severe draughts. During La Nina opposite climatic conditions prevail. Australia experiences heavy rainfall, India experiences moderate rainfall and Peru and Ecuador experience draught.

2. Answer any two question from the following :

Question 1.
Explain the major factors controlling the climate of India.
Answer:
The major factors that control the climate of India are :
i. Latitude: India lies between latitudes. The tropic of cancer runs through the middle of the country dividing the land into two distinct temperature zones. The southern part belongs to the Torrid Zone, While the northern part belongs to the Temperature Zone.

ii. Relief: Temperature is inversely proportionate to altitude. High relief regions have cooler climate compared to lower regions. Eg : some regions of Deccan plateau enjoy cool summers due to altitude, inspite of being nearer to the equator than the northern plains. The coastal regions enjoy an equable climate throughout the year.

iii. The Himalayas: The lofty Himalayas act as a barrier to the severely cold polar winds that come from the north, thus saving the country from chilling winters. It also prevents the monsoon winds from escaping northwards, thus ensuring monsoon rainfall in India.

iv. Distance from the sea: India has a very long coastline. The regions along the coastline enjoy moderate or maritime climate throughout the year due to the influence of the sea. Regions lying far from the sea experience extreme or continental climate with harsh summers and winters.

v. Winds: India lies under the prevailing north-eastern trade winds. Due to inequal heating of land and sea in different seasons, section of the wind blow seeasonally from oposite directions. These are called monsoon winds, They have a remarkable impact on the Indian climate and economy.

vi. Western disturbances: In winter, some cyclonic winds from the Mediteranean region, called western disturbances, enter India, causing a little rainfall and snowfall in the north.

vii. Jet Stream: This is a thin stream of speedy winds (350-450km/hr) blowing from west to east between the Troposphere and Stratosphere. These winds influence the onset and retreat of monsoons in India.

viii. El Nino and La Nina: During El Nino, India may experience rise in

Question 2.
Give an account of favourable physical conditions required for cultivation of tea in India.
Answer:
The favourable physical conditions required for the cultivation of tea in india are :

• Temperature: Tea can grow in temperatures between 10°c – 35°c. The best condition is 25°c  and growth is retarded below an average of 18°c.
• Rainfall: Tea requires 150-200 cm of annual rainfall well distributed throughout the year, with no long spells of dry season.
• Humidity: High humidity, heavy dews and morning fog favour rapid development of young leaves.
• Frost: Widespread winter frost is harmful for the growth of tea.
• Shade: Tea is a shade-loving plant. Hence big trees are planted in between tea plants to provide light and shade.
• Relief: Tea plants cannot tolerate stagnant of water at the base. Hence mountain slopes and undulating highlands are preferred for cultivation of tea.
• Soil: Well-drained sandy loam with porous sub-soil is favourable for tea. Virgin forest soils with good amout of iron and humus are also suitable.

Question 3.
Explain why cotton textile industry is extensively developed in Western India.
Answer:
The factors responsible for the extensive development of cotton textile industry in western india are :

• Availability of raw cotton from the black soil region of Western and Central India.
• Hot humid weather of western India helps in the growth of cotton and making of threads.
• Presence of ports at Mumbai, Kandla, Surat etc. helps in international trade.
• Availability of hydel power from Ukai, Veera, etc. thermal power from Dhubran, and atomic power from Kakrapara, Tarapore, etc.
• Good network of railways and roadways cannecting all important centres of the country.
• Availability of capital from business communitees residing in the western part of India.
• Ample labour at cheap rates.
• High demand of cotton products in the local and foreign markets.

Question 4.
Discuss the major problems of Urbanization in India.
Answer:
The major problems of urbanisation in India are :

• Unplanned growth of urban areas: Rapid concentration of population in urban areas lead to unplanned and nonsystematic growth of towns and cities,
• Accomodation: The rapidly growing population is difficult to house in the already existing urban areas, Hence, growth of slums and downtrodden areas occurs in the fringes of towns and cities.
• Availability of water: The amount of water available is not sufficient for the rapidly growing population. Hence scarcity of water occurs.
• Unemployment: A huge section of rural population comes to urban areas in search of work. But all of them do not get employment. Hence, the total percentage of unemployed population in the urban areas increases.
• Sewage and garbage disposal: The huge volume of disposable solid and liquid wastes generated by the excess population is difficult to handle with the present sewage and waste management systems. Thus waste dumping, water lagging, sewage overflow, etc. are common.

Group-F.

Locate the following with appropriate symbols and names on the given outline map of India. Attach the map with your answer paper: 1×10=10

1. Aravalli mountain.
2. River Narmada.
3. Highest rainfall receiving centre in north-east India.
4. Forest Research Institute of India.
5. A region of saline soil in eastern India.
6. A coffee producing region.
7. Rurh of India.
8. India’s largest IT industrial centre.
9. A natural port of Western India.
10. Largest megacity of Northern India.
OR
[For Sightless Candidates Only]
Answer:

6. Answer any ten of the following questions: 1×10=10

1. Name the rift valley lying between Vindhya and Satpura range.
2. Mention the name of the largest river island of India.
3. Name a coral island of India.
4. In which state of India, south-west monsoon wind strikes first?
5. Mention the name of state where mountain soils are found.
6. Which state of India ranks first in production of paddy?
7. Name one rabi crop produced in India.
8. Where in West Bengal rail engine manufacturing centre is located?
9. Name a mountain pass of Eastern Himalaya.
10. By which name, the old alluvial soil of Ganga Plain is known?
11. Name the state of India, having least population density.
12. Mention the name of the biggest port of Eastern India.
13. Which state of India ranks first in Coffee Production?
14. Name one natural port on the Eastern Coast of India.
Answer:
1. Aravalli mountain
2. River Normoda
3. Highest rainfall receiving centre in morth-east India
4. Forest research institute of India
5. A region of saline soil in eastern India.
6. A coffee producing region.
7. Rurh of India
8. India’s largest IT industrial centre.
9. A natural port of western India.
10. Largest mega city of Northern India.
OR.
[For sightless candidates only]
1. Narmoda river valley.
2 Majuli island on river Brahamaputra, Assam.
3. Lakshadweep islands.
4. Kerala
5. Sikkim, Jammu and Kashmir, Arunachal Pradesh, Assam.
6. West Bengal.
7. Wheat, barley, peas, gram, mustard, etc.
8. Chittaranjan
9. Nathula Pass, Bumla Pass
10. Bhangar
11. Arunachal Pradesh.
12. Chennai port
13. Karnataka
14. Kolkata port.