Class 7

Detailed explanations in West Bengal Board Class 7 History Book Solutions Chapter 1 The Idea of History offer valuable context and analysis.

WBBSE Class 7 History Chapter 1 Question Answer – The Idea of History

Very Short and short Questions & Answers :

Question 1.
What are the parameters of time in history?
Answer:
Date, month, year, century and millennium are important in history.

Question 2.
Which parameters of time are less important in history?
Answer:
Second, minute and hour are less important in history.

Question 3.
What is ‘History’?
Answer:
History is the study of human past as it is described in written documents left behind by humans.

Question 4.
Why is it important to study history?
Answer:
The study of history is important because it allows one to make more sense of the present world. One can look at past economic and cultural trends and be able to offer reasonable predictions of what will happen next in today’s world.

Question 5.
What are the sources of history?
Answer:
Old houses. temples and mosques, statues, coins, paintings, books and scripts are sources of history.

Question 6.
What are the types of sources of history?
Answer:
There are two main types of historical sources–

• Primary sources,
• Secondary Sources.

Question 7.
What is primary source of history?
Answer:
Sources contain firsthand knowledge of events and people and essential to a good research project is called primary sources.

Question 8.
What is secondary source of history?
Answer:
Secondary source is something that was not created first-hand by someone who participated in the historical era.

Question 9.
In how many parts history is divided?
Answer:
History is divided into three parts :

• ancient.
• medieval and
• modern age.

Question 10.
Why are coin important for the study of medieval period?
Answer:
Coin tells us about the reigning periods of kings and gives us dates of political events.
It also tells us about the economy of kingdom and trade with other regions.

Question 11.
Why are inscriptions important for the study of medieval period?
Answer:
Inscriptions are record of royal proclamation, religious instruction and gifts given by rulers. It tells us important events in king’s life. about the people of particular time and narrates the achievements of the king.

Question 12.
Who used the word ‘India’ first?
Answer:
The word India was first used by the Greek historian Herodotus..

Question 13.
How do historians devide the past into periods?
Answer:
The fistorians devide the past into periods on the basis of economic and social factors to characterise the maine elements of different moments of the past.

Question 14.
What was considered a ‘foreigner’ in the past?
Answer:
Any stranger who did not belong to a certain society or culture and was not a part of that particular village was regarded as a foreigner.

Question 15.
Mention some of the technological changes associated with medieval age in India. is
Answer:
Some technological changes are —

• Use of spinning wheel in weaving.
• Use of Persian wheel in irrigation.
• Use of fire arms in combat.

Question 16.
What were some of the major religious developments during medieval age?
Answer:
Some religious developments are–

• Worship of new deities.
• Increasing importance of Brahmans, the priests as dominant group of the society.
• The imergence of the idea of Bhakti among people.
• Appearance of many new religions like islam.

Question 17.
In what ways has the meaning of the term ‘Hinduthan’ changed over the centuries?
Answer:

• In the thirteenth century, the term ‘Hindusthan’ was used for the first time by Minhaj-i-Siraj, a Persian clironicler.
• During the fourteenth century, the term ‘Hind’ was used by Amir Khasru to refer to the culture and people of the Indus river.
• During the early sixteen century, Babar used the term ‘Hindusthan’ to describe the culture, geography and fauna of the inhabitants of the sub-continent.

Question 18.
What was significant changes in governance and politics?
Answer:
The rulers had to think not only of territorial expansion but also about the well-being of the subjects.

Question 19.
What was significant changes in economic sphere?
Answer:
There was agriculture on the one hand and commerce on the other hand. New towns were esablished. Forests were cleared to extend cultivation land.

Fill in the blanks : ( 1 mark for each question)

1. ‘Hindusthan’ was used to indicate the whole of ______
Answer:
India.

2. Inscriptions on copper plates are called _______
Answer:
Copper inscriptions.

3. Inscriptions on stone plaques are called _______
Answer:
Stone inscriptions

4. Those that are written on paper are called ________
Answer:
Paper materials.

5. People of India came to know of various food item and beverages in ______ period. it
Answer:
Medieval.

6. Different fields of art were _______ in medieval period.
Answer:
explored.

7. Historians look bits and pieces of _____
Answer:
evidence.

8. We do not know the names of the multitude of ______ and ______ who actually built the Taj Mahal.
Answer:
carftsmen, artisans.

9. People of medieval period discovered some new avenues in ______ thinking.
Answer:
religious

10. Historians have divided a long period of time by ______.
Answer:
age.

State whether True or False : ( 1 mark for each question)

1. In medieval period there was no development in any field.
Answer:
False

2. Hindustan was mentioned in Arabic and Persian sources.
Answer:
True

3. Many people use the word ‘desh’ to mean their native land.
Answer:
True

4. Calculation of stine of great value in history.
Answer:
False

5. Everyone likes of bygone days, if they are narrated like stories
Answer:
True.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 6 Rock and Soil offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 6 Question Answer – Rock and Soil

(Page no. 62)
Let’s get the job on hand done….

ORIGIN OF ROCKS	TYPES OF ROCK
1. By sedimentation	Sedimentary rock.
2. By accumulation of Lava	Igneous rock
3. By heat and pressure in the earth’s interior	Metamorphic rock

Charecteristics of RoCK	TIPES OF ROCK
1. Light and brittle	Sedimentary rock
2. Hard and resistant to erosion	Metamorphic rock.

(Page no. 64)

Class 7 Geography Chapter 6 Question Answer West Bengal Board – Rock and Soil

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
The rock that accumulates on the ocean floor is –
i) igneous rock
ii) sedimentary rock
iii) metamorphic rock
Answer:
ii) Sedimentary rock.

Question 2.
The rock that is used in making cement is –
i) mudstone
ii) sand stone
iii) lime stone
Answer:
iii) Lime stone.

Question 3.
Marbel is –
i) igneous rock
ii) sedimentary rock
ii) metamorphic rocks
Answer:
iii) Metamorphic rock.

Question 4.
Sedimentary rock is –
i) sand stone
ii) granite
iii) basalt
iv) marble
Answer:
i) Sand stone.

Question 5.
The stones that are used as building materials –
i) limestone
ii) sandstone
iii) mudstone
iv) sandstone and mudstone
Answer:
iv) sandstone and mudstone

Question 6.
The grains of sandy soil is –
i) fine
ii) medium
iii) coarse
Answer:
iii) coarse.

Question 7.
Loamy soil contains-
i) more sand, less clay
ii) equal sand and clay
iii) less sand, more clay
Answer:
ii) equal sand and clay

Question 8.
The animals help to loosen the soil-
i) ants
ii) moles
iii) earthworms
iv) all of these
Answer:
iv) all of these

Fill in the blanks : (1 mark for each question)

1. Granite is one type of ________.
Answer:
ignious rock

2. Tajmahal is made of __________.
Answer:
marbel

3. Soil forms faster in warm and rainy ___________.
Answer:
climates

4. Dead remains of organisms supply ___________ to a soil.
Answer:
nutrients

5. Sandstone, mudstone, limestone are examples of _________ rocks.
Answer:
sedimentary

6. Plants and animals form a very __________ part soil.
Answer: small

7. soil __________ is best suited for cultivation.
Answer:
Loamy

8. The hard outer shell of the earth is made of __________.
Answer:
rocks

9. ____________ soil has bigger grains and bigger spaces between the grains.
Answer:
sandy

10. Sandy soil absorbs ____________ in no time.
Answer:
water

11. The __________ soil is found at the bank of the river.
Answer:
alluvial

12. The ability of holding water is more is ___________ soil.
ins :
clayey

State whetherTrue or False : (1 mark for each question)

1. The earth was a ball of fire when it was born.
Answer:
true

2. Igneous rocks break down easily.
Answer:
false

3. Sandstone is used as raw material in cement.
Answer:
false

4. Metamorphic rocks are hardy and resistant to errosion.
Answer:
true

5. Heat from the sun, rain drop, wind, river water etc break down the rocks.
Answer:
true

6. Soil formation is influenced by several factors.
Answer:
true

7. Soil is classified on the basis of their taste.
Answer:
false

8. Basalt is the example of sedimentary rock.
Answer:
false

9. Sedimentary rocks are soft and brittle.
Answer:
true

Match the following : (1 mark for each question)

Match column A with column B.

A	B
a) Igneous rock is	i) soft and brittle
b) Granite and Basalt are	ii) warm and rainy climates
c) Limestone is used	iii) supply nutrients to soil
d) Sedientary rock is	iv) example of igneons rock
e) Metamorphic rock is	v) very hard
f) Soil forms faster in	vi) equal sand and clay
g) Dead remains of organisms	vii) resistant to erosion
h) Loamy soil contains	viii) in cement

Answer:
a) Igneous rock is very hard.
b) Granite and Basalt are example of igneous rock.
c) Limestone is used in cement.
d) Sedientary rock is soft and brittle.
e) Metamorphic rock is resistant to erosion.
f) Soil forms faster in warm and rainy climates.
g) Dead remains of organisms supply nutrients to soil.
h) Loamy soil contains equal sand and clay.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What type of rocks are those which lie on the railway track?
Answer:
The rocks on the railway track are igneous rock.

Question 2.
Which rock can resist erosion?
Answer:
Metamorphic rock can resist erosion.

Question 3.
Which rocks are used as housebuilding materials?
Answer:
Sandstone and mudstone are used as house building materials.

Question 4.
Which soil is suitable for agriculture?
Answer:
Loamy soil is suitable for agriculture.

Question 5.
What do the rocks transform into after erosion?
Answer:
After erosion the rocks transform into soil.

Question 6.
Which soil can not hold water?
Answer:
Sandy soil can not hold water.

Question 7.
Which soil is used for making idol?
Answer:
Clayey soil is used for making idoal.

Question 8.
What is the Earth’s surface?
Answer:
The outmost level of the land or sea is known as the Earth’s surface.

Question 9.
What are rocks?
Answer:
Rocks are the compound of minerals which form the Earth’s surface.

Question 10.
How are the rocks classified?
Answer:
Rocks are classified into three groups- igneous, sedimentary and metamorphic.

Question 11.
What is soil?
Answer:
The smooth and loose upper most rock layer of the earth’s surface is called soil.

Question 12.
How is the soil classified?
Answer:
The soil is classified into three group-sanday, clayey and loamy.

Short Questions & Answers : (2 marks for each question)

Question 1.
What is igneous rock?
Answer:
The hot molten magma of earth chamber when comes out through an openings of the earth surface and forms hard rocks by cooling down in contact with cool air. This is called ignious rock.

Question 2.
What is sedimentary rock?
Answer:
Different types of rocks are weathered by some natural forces and accumulate on the ocean flore. In due course of time due to the pressure of upper layer of the rocks and the heat of the earth core the sediment turn into rocks. This is called sedimentary rock.

Question 3.
What is metamorphic rock.
Answer:
When the igneous and sedimentary rocks due to the action of different natural forces like river wind, glacier etc, converted into a new type of rocks, this is called metamorfic rock. Example—marbel.

Question 4.
What is fossils.
Answer:
When an animal body is stored with the sediment and burried under the layer of sediment, in due course of time it solidifies and turn into rock. This animal body leaves mark on the rock. this is called fossil.

Long Questions & Answers : (3 marks for each question)

Question 1.
Write the features of igneous rocks.
Answer:

1. As the molten material solidify to form the ignec’is rocks, it is crystalized
2. It has no layer.
3. This types of rock does not break easily, it is comperatively hard.
4. The fossil can not be found in this rock.

Question 2.
Write the features of the sedimentary rock.
Answer:

1. It has layers.
2. It is soft and light.
3. Sedimentary rock erodes easily,
4. Fossils are found in this rock,
5. This type of rock is not crystalized.

Question 3.
Write the charatersites of metamorphic rock.
Answer:

1. This rock is crystalized,
2. When the sedimentary rock turns into metamorphic rock, it becomes hard.
3. Fossils are not found when sedimentary rocks change into metamorphic.
4. The minerals of metamorphic rocks are accumulated in one side.

Question 4.
What is rock cycle?
Answer:
The rock cycle is the process by which rocks of one kind change into rocks of another kind. There are three main kinds of rocks: igneous rock, metamorphic rock and sedinientary rock. Each of these rocks can change in to the other kinds by physical process : cooling. melting, heating, weathering. compacting, cementing and pressure.

Question 5.
Write the different use of alluvial soil.
Answer:
a) Alluvial soil is suitable for agriculture.
b) It is used for making idol.
c) The potter uses the soil for making pots.
d) It is used for making hut.

Question 6.
State the characteristics lies of different soils.
Answer:
Sandy soil : i) The grains of this soil are large. 2) It can not hold more water. 3) Air can passes through this soil. 4) It is not fertile. 5) It is not fit for agriculture.
Clayey soil : i) The grains of the soil is very fine. ii) The capasity of holding air is more. iii) Air can not pass through this soil easily. iv) It can not be broken easily if it becomes dry. v) Dust clayey soil is like powder.
Loamy soil : i) It is fit for agriculter. ii) The grains of the soil is medium. iii) The ability of holding water is medium. iv) The ablity of passing air is medium.

Question 7.
Classify the igneous rock according to their origin.
Answer:
According to their origin ignious rocks are of two types-i) Intrusive rock, ii) Extrusive rock. Intrusive rock is further divided into two types : a) Plutonie rock, b) hypabyssal rock.

When the hot molten lava of earth chamber can not reach on the earth’s surface it cools down in the earth’s chamber for many years and solidifies. This is called intrusive rock.

In the earth chamber when the magma cools down and solidifies to form a rock it is called plutonic rock. On the other hand when the magma cools down and solidifies in the crack before reaching the earth surface, this is called hypobyssal rock. Granite is the example of hypobyssal.

When the magma comes out through the crater of the volcano at the time of volcanic erruption, it cools down and solidify in contact of coal air then it is called extrusive rock. Basalt is the example of extrusive rock.

Question 8.
What are the differences between igneous rock and sedimentry rock.
Answer:
a) Fossils can not be found in igneous rock. Fossils are found in sedimentary rocks.
b) Igneous is the rock of primery stage. Sedimentary rock is the rock of second stage.
c) Igneous rock is formed either on earth’s surface or in the earth’ chamber and sedimentary rock is formed under the ocean.
d) Ignious rock is crystalized but sedimentary rock is not crystalized.
e) There is no layer in igneous rock but layers are found in sedimentary rocks.
f) lgneous rock is hard but sedimentary rock is less hard

Question 9.
Why is fossil found in sedimentary rocks?
Answer:
Fossil is found in sedimentary rocks because sedimentary rock is formed under the sea or lake by accumulating sediment layer by layer. then the dead body of marine plants or animals are burried at the time of accumulating sediment and solidifies to form rock. After that the mark of their bodies are left in rock layers. So the fossils are found in sedimentary rocks. As the formation of the sedimentary rocks is a long process, in the long past the fossils of the animals that appeared in different ages can be found in the sedimentary rocks and it helps us to gain knowledge about the ancient plants and animals or the climate of that ages.

Additional Questions and answers :

Question 1.
Mention the factors of formation of soil.
Answer:
Rocks: The characteristics of a soil depend on the nature of rock(s) from which it is derived. However, soil formation is also influenced by several other factors.

Climate : Climate plays a very significant role in the formation of soil. Soil forms faster in warm and rainy climates and takes a lot of time to form in cool and dry climates. So, deeper soils are generally found in warm and humid regions.

Relief: the relief of the land influences the processes of formation of soil. Soil is unlikely to form on steep slopes. Gentler slopes support better and gradual development of soil.

Organic matter : plants and animals, alive or dead, form a very small part of soil, but are very significant. Ants, moles, earthworms and snakes loosen the soil and let air and water enter in to it. Dead remains of organisms supply nutrients to a soil.

Time : Soil does not form in a day. The natural process of soil formation may span through thousands, and sometimes, even millions of year.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 5 River offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 5 Question Answer – River

Verify and say…(Page no. 52)

Where do you find water flowing faster?
i) On a flst surface
ii) On a slope
Answer:
ii) On a slope

When does water flow faster on slopes?
i) When the volume of water is more
ii) When the volume of water is less
Answer:
i) When the volume of water is more

Think and write down (Page no. 53)

Fill it up correctly (Page no. 57)

You can fill this up from the village (Page no. 59)

Benefits derived from a river	Their influence on our lives
Water	drinking water, bathing, industry
Alluvium, Plains	Cultivation, urbanisation, prosperity of civilizations
Flood plains, agricultural land	agriculture, animal husbandry
Irrigation	production of crops, vegetables, fruits
Hydro electricity	agriculture, industry, daily use
Fish and aquatic life in river	fishery, food
Transportation	trade & commerce, transport
Tourism, amusement, environment, ecological balance	River water and sediments as habitat to plants, animals and microbes; replenishment of the underground water table

Look for the words (Page no. 59)

Clue
Where a river meets the sea–Estaury
River in which water flows throughout the year–Perennial
River originating from a main river–Distributary
A highland that makes rainwater runoff to different sides to form rivers flowing in different directions–Water shed
Deep cut river valley in a dry region–Cannyan
River water falls from a height along a slope to form a …–Waterfall
Alluvium is deposited along both banks of a river during flood to form…–Flood plain

Class 7 Geography Chapter 5 Question Answer West Bengal Board – River

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
The river Ganga is from Gomukh to Haridwar in-
i) upper course
ii) middle course
iii) lower course
Answer:
i) upper course

Question 2.
In the upper course, the river mainly-
i) deposits
ii) erodes
iii) transports its load
Answer:
ii) erodes

Question 3.
In the lower course, the river mainly-
i) deposits
ii) erodes
iii) transports its load
Answer:
i) deposits

Question 4.
In upper course the river forms-
i) meander
ii) waterfalls
iii) island
iv) ox-bow lake
Answer:
ii) Waterfalls.

Question 5.
The landform that creates in the middle course of the river is-
i) waterfall
ii) flood plain
iii) canyon
iv) ox-bow lake
Answer:
iv) Oxbow lake.

Question 6.
In the upper cource of a river it is-
i) calm
ii) exhausted
iii) restless
iv) gentle
Answer:
iii) restless

Question 7.
The river that gets water through out year is called-
i) perennial
ii) non perennial
iii) inland
Answer:
i) Perernnial.

Question 8.
The middle course of ganga is-
i) from Gomukh to Haridwar
ii) from Mithipur to mouth of the river
iii) from Haridwar to Mithipur
Ans.
iii) from Haridwar to Mithipur

Question 9.
Egyptian Sivilization thrived on the bank of river-
i) Indus
ii) Hwang Ho
iii) Nile
iv) Euphrates
Answer:
iii) Nile

Question 10.
The rivers have affected the growth of-
i) agriculture
ii) industry
iii) urbanisation
iv) all these
Answer:
iv) all these

Question 11.
The Jog fallsin the Western Ghats of India is-
i) 260 m high
ii) 360 m high
iii) 350 m high
iv) 250 m high
Answer:
i) 260 m high

Question 12.
The length of Amazon river is –
i) 6000 km
ii) 6200 km
iii) 6300 km
iv) 6400 km
Answer:
iv) 6400 km

Question 13.
The length of Mississippi river of North America is-
i) 3700 km
ii) 3730 km
iii) 3500 km
iv) 3600 km
Answer:
ii) 3730 km

Fill in the blanks : (1 mark for each question)

1. An Ideal river is ____.
Answer:
Ganga.

2. Taking a winding path of the river is called ____.
Answer:
meander.

3. In ____course of the river canyon is formed.
Answer:
upper.

4. The mouth of the river Ganga is ____.
Answer:
Bay of Bengal.

5. The longest river in the world is the ____.
Answer:
Nile.

6. When a small stream falls in the main river is called ____.
Answer:
tributary.

7. The area drained by a river from source to mouth is called ____.
Answer:
river valley.

8. An inland river of India is ____.
Answer:
Luni.

9. The area lying between the two rivers is called ____.
Answer:
Doab.

10. The deep valley in dry region is called ____.
Answer:
canyon.

11. The length of the river Amazon in South America is ____.
Answer:
6,400 km

12. The length of the river Murray Darling in Oceania is ____.
Answer:
3,375 km

13. Ganga originates from ____ in Gangotri glacier.
Answer:
Gomukh

14. ____ in Asia is an International river.
Answer:
Brahmaputra

15. ____ are shown by black lines on maps.
Answer:
Non-perennial rivers

State whether True or False : (1 mark for each question)

1. The energy of a river is high in the mountains.
Answer:
true

2. Grand Canyon of Colorado is situated in USA.
Answer:
true

3. Deposition is the main work of a river in the middle course.
Answer:
false

4. The length of Missouri is 3,710km.
Answer:
false

5. Perennial rivers do not dry up during any time of the year.
Answer:
true

6. Middle course of a river is compared with an old man.
Answer:
false

7. Main work of a river in the middle course is to travsport ane deposit.
Answer:
true

8. In upper course, the river valley does not become very broad.
Answer:
true

9. Meanders are formed in the middle course of a river.
Answer:
true

10. Every river can form delta at its mouth.
Answer:
false

11. In lower course of Hwavg-Ho river has Flood plains.
Answer:
true

12. There is less erosion in the upper course of a river.
Answer:
false

Match the following : (1 mark for each question)

a) Match the column A with column B.

Column A	Column B
a) The river in its upper course	i) is 260 m high
b) The river in its lower course	ii) 6650 km
c) Grand Canyon of Colorado	iii) its power is reduced
d) Jog falls in the Western ghat	iv) mainly deposits
e) The length of Nile is	v) on the banks of rivers
f) The area between two river-beds	vi) mainly erodes
g) Near its source a river has	vii) end at its sonfluence
h) A river deposits more when	viii) is a famous canyon
i) The course of a river cpmes to an	ix) is called Doab
j) Earliest civilizations thrived	x) great speed and energy

Answer:
a) The river in its upper course mainly erodes.
b) The river in its lower course mainly deposits.
c) Grand Camyon of Colorado is a famous canyon.
d) Jog falls in the Western ghat is 260 m high.
e) The length of Nile is is 6650 km.
f) The area between two river-beds is called Doab.
g) Near its source a river has great speed and energy.
h) A river deposits more when its power is reduced.
i) The course of a river comes to an end at its confluence.
j) Earliest civilizations thrived on the banks of rivers.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What is river?
Answer:
When a stream of water originates from a source and flows from higher region to lower region according to the slope of the land is called river.

Question 2.
What is the source of a river?
Answer:
The place from where the river originates is called the source of the river.

Question 3.
What is the unit of the measuring river water?
Answer:
The unit of measuring river water is cusek.

Question 4.
In which course of the river meander is formed?
Answer:
Meander is formed in the middle course of a river.

Question 5.
In which course of the river flood plain is formed?
Answer:
Flood plain is formed in the lower course of a river.

Question 6.
In which course of the river waterfall is formed?
Answer:
waterfall is formed in the upper course of a river.

Question 7.
In which course of the river ox-bow lake is formed?
Answer:
Ox-bow lake is formed in the middle course of a river:

Question 8.
In which course of the river canyon is formed?
Answer:
Canyon is formed in the upper course of a river.

Question 9.
In which course of the river river island is formed?
Answer:
River island is formed in the niddle course of a river.

Question 10.
In which course of the river delta is formed?
Answer:
Delta is formed in the lower course of a river.

Question 11.
What is the main function of a river in upper course?
Answer:
Erosion is the main function in the upper course of a river.

Question 12.
What is the main function of a river in middle course?
Answer:
The main function of a river in the middle course of a river is to transport and deposit.

Question 13.
What is the main function of a river in lower course?
Answer:
Deposition is the main function of a river in lower course of a river.

Question 14.
Mention the upper course of Ganga.
Answer:
The upper course of Ganga is from Gomukh to Haridwar.

Question 15.
Mention the middle course of Ganga.
Answer:
The middle course of Ganga is from Haridwar to Mithipur in murshidabad.

Question 16.
Mention the lower course of Ganga.
Answer:
The lower course of Ganga is from Mithipur in murshidabad to the mouth of the river in Bay of Bengal.

Question 17.
In which course of the river canyon is formed?
Answer:
Canyon is formed in the upper course of a river.

Question 18.
What are the two main distributaries of the river Ganga?
Answer:
The main two distributaries of the river ganga is Bhagirathi and Padma.

Question 19.
What is the meaning of the word ‘Doab’?
Answer:
‘Do’ means two and ‘ab’ means water/river.

Question 20.
What is the largest delta of the world?
Answer:
The largest delta of the world is the delta of the river Ganga.

Question 21.
What is river valley?
Answer:
The area through which the river and its tributaries flow is called river valley.

Question 22.
What is water shed?
Answer:
The land that separates the two or more than two rivers flowing side by side is called the water shed.

Question 23.
What is an ideal river?
Answer:
The river in which the three courses upper, middle and lower course are found is called the ideal river.

Question 24.
On which factors the force of the river depends?
Answer:
The force of the river depends on the slope of the valley, the nature of the rocks. the shape and the weight of the load etc.

Short Questions & Answers : (2 marks for each question)

Question 1.
What is international river? Give examples.
Answer:
The river that flows through more than one countries is called international river. Brahmaputra in Asia, Rhine and Danube in Europe are two examples of international river.

Question 2.
What is inland river? Give examples.
Answer:
A river emptying itself into an inland lake or any other inland water body is called an inland river. Luni in India and Amur in Russia are examples of inland river.

Question 3.
What is tributary? Give examples.
Answer:
A stream originating from any source and emptying itself into a larger river is called a tributary. Yamuna, Gandak, Gharghara are all tributaries of the Ganga.

Question 4.
What is George and Cannyon?
Answer:
In the mountain region if the rever valley is very narrow and deep like ‘I’ or ‘V’ shaped, then it is called george. When the George is in dry ares it is called Canyon.

Question 5.
How is waterfall formed?
Answer:
In the upper course of the river if hard and soft -rocks are arranged in alternate layers. the softer layers get eroded faster and step-like features are formed. Now the the water now plunges down these steep-sided and form waterfalls.

Question 6.
What is Estuary?
Answer:
At the meeting point of the river and sea the river valley becomes wide. At the time of high tide the saline water of see enters the river through its mouth and form estuary by widen the mouth. Muddy water is found is the mouth of the river and the river vaitey becomes wide.

Question 7.
What is flood plain? Give examples.
Answer:
In the lower course of a river the flood waters leave sediments in the extensive plain lands on both banks of the river, thereby form flood plain. The lower course of the \mathrm{Hv How has flood plains.

Question 8.
What is perennial river?
Answer:
The streams with their sources high up in the mountains are generally fed by ice-melt water. The channels do not dry up during any time of the year. Such type of river is called perennial river.

Question 9.
What is non-perennial river?
Answer:
There are some rivers which are filled with water during rainy season. During other parts of the year their channels tend to dry up. They are called non-perennial rivers.

Long Questions & Answers : (3 marks for each question)

Question 1.
Why is ‘V’ shaped valley formed in the upper course of the river?
Answer:
In t e upper course of the river the velocity of the water is high and so the water break the pelbbles and boulders into small pieces and are transported by the water. These pebbles and boulders struck the river bed. So lower cut is more than the side cut. Therefore the V shaped valley is formed in the upper course of the river.

Question 2.
Why is the delta not found in all river.
Answer:
The deposition is much in the lower course of the river. The eroded silt, mud, pebbles. sands brought by the river accumulate at the mouth of the river to form delta. Sometimes in many rivers the lower course could not be found or the amount of the load may be less. Besides if the water current is more the delta could not be formed.

Question 3.
What are the different functions of the river?
Answer:
The function of the rivers are of three types-i) Erotion, ii) Transportation and iii) deposition.

1. Erosion : The river struck the side rocks by the water current in upper course.
2. Transportation : The eroded rock particles are transported by the river water.
3. Deposition : The eroded rock particles are accumulated at the river bed and the mouth of the river in the lower course. This is called deposition.

Question 4.
Compare the function of the river in different courses.
Answer:

Question 5.
What are the different landforms created in the upper course of the river?
Answer:
The different landfroms created in the upper course :
i) Narrow ‘V’ shsped Valley : In upper course the lower cut of the river is more than side cut. Thus the ‘V’ shaped valley formed. This type of valley when becomes more deep it is called George. But in the desert area with limestone the upper cut is only occured, thus the river valley is ‘I’ shaped here. This is called Cannyon.

ii) Water fall : In the upper course of the river if the hard and soft rock bed lie horizontally, the soft rock erodes faster then hard rock and the hard rock forms step like structure and river water falls from higher to laower slope which is known as waterfalls. Sometimes water falls occurs in the upper course due to fault.

iii) Pot hole : when the boulders or rocks are carried by the river water they may strike the river bed and create holes. These are called poese holes.

Question 6.
What are the different land forms created in lower course.
Answer:
Old age of the river found after the middle course. This is called lower course. This is called main river valley. The main function of the river in lower course is deposition. The landform created by deposition are-i) delta, ii) flod plain.

i) Delta : When the river falls in the sea or lake it stops flowing and can not go any more in the sea. Thus the silt accumulae in the sea bed. The sedimentation is more in saline water. Years after years the accumulation of silt forms delta at the mouth of the river. The landform is triangular shaped or greek ‘Δ’ shape. The silt accumulaes at the river bed day by day and the delta increases towards the sea and the sea goes away from the land. For this reason the mouth of the river graduaily expands.

ii) Flood plain : The accumulation of sediments on the river bed makes it shallow. So the river overflows its banks during the rainy season. The flood waters leave behind cediments in the existensive plain lands on both banks of the river and form flood plains.

Question 7.
What are the different process of erosion?
Answer:
The different process of erosion are-i) abration, ii) attrition, iii) Corrosion, iv) Hydrolic action.

1. Abrasion : The rocks, pebbles. brought by the river, erode the river bed. This type of erosion is called abrasion which creats potholes in the river bed.
2. Attrition : The pieces of rocks. brought by the river, gradually become smaller by striking each other at last turn into sand. This is called attrition. For this the pebbles become round shaped.
3. Corrosion or solution : In the course of the river sometimes minerals present in the rocks in some places. Which desolve in the water and becomes eroded. This is erorsion by solution. This type of erosion is found in limestone area.
4. Hydrodlic action : When the river water flows violently, it strikes the two sides of the river valley. For this reason the comperatively soft rocks gradually erode. This type of erosion makes the river valley.

Question 8.
What are the different landforms created in the middle course of the river due to the deposition.
Answer:
The slope of the river decreases in the middle course of the river. Eroded materials are accumulated at the both side of the river bank and in the river bed.

i) Meander : In the middle course the velocity of the river water decreases and the river flows slowly. In this situation the river meanders when it gets obstructed. This is called meander. Meanders are found it the river Ganga near Baranasi.

ii) Sand bars, River Islands : In the middle course of a river its capacity to carry eroded materials is also reduced. Its starts depositing the transported pebbles, sand and silt on its bed and along the banks. This deposits may choke the channel and form sand bars, or sometimes, river islands.

iii) Ox-bow lake : The more a river meanders, or the more volume of water flows through it, the loop of the meander can get seperated from the main channel by reverine deposits. This seperated part generally has the shape of a horse-shoe and is called an ox-bow lake.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 4 Landforms offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 4 Question Answer – Landforms

Match the following (Page no. 40) 

1. Etna	Fold Mountain
2. Alps	Igneous Mountain
3. Black Forest	Fold Mountain Forest
4. Himalaya	Black Mountain

Answer:

1. Etna	Igneous Mountain
2. Alps	Fold Mountain
3. Black Forest	Black Mountain
4. Himalaya	Fold Mountain

Brainware-Solve it if you grasp it. (Page no. 42)

Answer:
Mountain

1. Height-More than 900 m
2. Charecteristics-For extended rocky mass with steep slope.
3. Charecteristics-Conical narrow upper portion known as peak.
4. Types-Fold Mountain, volcanic Mountain, Black Mountain.

Plateau

1. Height-300-600 m
2. Highest plateau-Pamir plateau
3. Charecteristics-Land with steep slope at its side with plat or undulating top.
4. Example : Pamir plateau, Tibetian plateau, Indian Chotanagpur plateau.

Plain :

1. Charecteristcs-Almost Flat land.
2. Type-Alluvial plain, Lava plain, Loess plain.
3. Example : Ganga-Brahmaputra plain, Loess plain of China, Hwong-Ho plain.

Effect of of Landforms on Human life- (Page no. 45)

a) Mountain Region :

Question 1.
What can be the main livelihood?
Answer:
Animal Husbandary, Lumbering Industry, Tourism.

Question 2.
What should be the transport system?
Answer:
Bad.

Question 3.
How are settlement and density of population likely to be?
Answer:
Low

Question 4.
How is the economic development likely to be?
Answer:
Low.

Question 5.
Lifestyle?
Answer:
Very Tough.

B. Plateau Region :

Question 1.
What can be the main livelihood?
Answer:
Industry and mining.

Question 2.
What should be the transport system?
Answer:
Medium.

Question 3.
How are settlement and density of population likely to be?
Answer:
Medium.

Question 4.
How is the economic development likely to be?
Answer:
Medium

Question 5.
Lifestyle?
Answer:
Very Tough

C. Plain Region :

Question 1.
What can be the main livelihood?
Answer:
Agriculture, Entertainment Industry, Animal husbandry.

Question 2.
What should be the transport system?
Answer:
Very good.

Question 3.
How are settlement and density of population likely to be?
Answer:
Very high.

Question 4.
How is the economic development likely to be?
Answer:
High.

Question 5.
Lifestyle?
Answer:
Medium.

Crossword :

Across
1. Landforms exceeding1000 m in height.
6. A famous hill station in South India.
7. A volcano in Sicily.

Up-Down
2. Fold Mountain in North America.
3. Block mountain in India.
4. Intermontane plateau between Himalayas and Kunlun.
5. Darjeeling is a famous spot

Class 7 Geography Chapter 4 Question Answer West Bengal Board – Landforms

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
An endogentic force is –
i) sea waves
ii) radiation from the sun
iii) earth movement
Answer:
iii) earth movement

Question 2.
An old fold meantain of India is –
i) himalay
ii) Araballi
iii) Satpura
Answer:
ii) Araballi

Question 3.
According to the mode of origin mountains are of –
i) two types
ii) four types
iii) five types
iv) three types
Answer:
iv) three types

Question 4.
The hight of Mt. Everest is –
i) 8840 m
ii) 8844 m
iii) 8848 m
iv) 4488 m
Answer:
iii) 8848 m

Question 5.
Fold is responsible for formation of –
i) block mountain
ii) fold mountain
iii) volcanic mountain
Answer:
i) block mountain

Question 6.
The largest plateau of the world is –
i) Colorado plateau
ii) Anatolian Plateau
iii) Tibetan Plateau
iv) Decan plateau
Answer:
iii) Tibet Plateau.

Question 7.
River based civilizations are formed at –
i) mountain region
ii) plateau region
iii) plain region
Answer:
iii) Plain region

Question 8.
Decan plateau is best example of –
i) lava
ii) continental
iii) piedmont
iv) intermontane
Answer:
i) lava.

Question 9.
Generally a plateau is –
i) 250 m high
ii) above300 m high
iii) below300 m high
iii)200 m high
Answer:
ii) above300 m high

Question 10.
Many mountain ranges converging at a place forms a –
i) peak
ii) valley
iii) mountain range
iv) mountain knot
Answer:
iv) mountain knot

Question 11.
Visuvius is situated in-
i) Africa
ii) Japan
iii) Italy
iv) Indonesia
Answer:
iii) Italy

Question 12.
Mountains are generally higher than –
i) 300 m
ii) 900 m
iii) 600 m
iv) 700 m
Answer:
ii) 900 m

Question 13.
A famous plain land of Asia-
i) Gangetic Plains
ii) Pampas
iii) Prairries
iii) plains of Nile
Answer:
i) Gangetic Plains

Question 14.
Satpura in India is a-
i) Volcanic mountain
ii) Fold mountain
iii) Block mountain
Answer:
iii) Block mountain

Question 15.
Most plateaus are very rich in –
i) agriculture
ii) industry
iii) tourism
iv) minerals

Question 16.
Pampas is situated in –
i) North America
ii) South America
iii) Africa
iv) Asia
Answer:
ii) South America

Question 17.
A contintinental plateau-
i) Greenland
ii) Malwa
iii) Chhotanagpur
iv) Tibet
Answer:
i) Greenland

Fill in the blanks : (1 mark for each question)

1. The diversity of earth’s surface is called ________.
Answer:
Landfrom

2. Glacier is the Earth’s ________.
Answer:
exogentic

3. The highest peak of the world is ________.
Answer:
Mt. Everest

4. Lowland between two high ridges is called ________.
Answer:
vally.

5. The plateau is called ________.
Answer:
table land.

6. A plain of south America is ________.
Answer:
Pompus.

7. The Chhotanagpur plateau is a ________.
Answer:
dissected Plateau.

8. The forest of ________ wood is found in mountain region.
Answer:
soft.

9. ________ plateau is best example of Volcanic Plateau.
Answer:
Decan.

10. ________ is North America one the world’s largest alluvial plain.
Answer:
Prairie

11. The world’s highest inter moutain plateau is situated in between Himalaya and ________ mountain.
Answer:
Kuniti:.

12. When Mountain peaks and valleys extended laterrally is called Mountain ________.
Answer:
chain.

13. When a few mountain chains meet in a highland is called Mountain ________.
Answer:
knot.

14. The top of a plateau may be flat or ________.
Answer:
undulating.

15. Forces from the earth’s ________ as well as those from outside can shape various types of plains.
Answer:
interior.

State whether True or False : (1 mark for each question)

1. Lava plains can be seen in iceland.
Answer:
true

2. A plateau is also called a table land.
Answer:
true

3. The hight of pamir plateau is 3973 m.
Answer:
false

4. Nile in North America is a famous plain.
Answer:
false

5. About one-fourth of the landmass on earth is mountain.
Answer:
true

6. Vesuvias in Italy is a volcanic mountain.
Answer:
true

7. Vosges in Italy is a voicanic mountain.
Answer:
false

8. Alps in Europe is a fold mountain.
Answer:
true

9. The surface of the earth is not similar everywhere.
Answer:
true

10. The highest parts of the earth’s surface are plains.
Answer:
false

11. The interior of the earth always undergoes movements.
Answer:
true

12. Rivers, winds, glaciers and sea waves are sndogenic process.
Answer:
false

13. The narrow, pointed summits of the mountains are salled peaks.
Answer:
true

14. Most of the plains in the world have been formed by the deposition of alluvium.
Answer:
true

Match the column A with column B.

Column A	Column B
a) Prairries in North America—	i) an alluvial plains
b) The Tibet plateau is	ii) a table land
c) The Chhotanagpur plateau is	iii) mountainous tourist spot
d) Pamir plateau is known as	iv) one of the famous plains of the world
e) Indo-Ganga-Brahmaputra plains is	v) $3655 \mathrm{~m}$ high
f) Antertica is a	vi) lava plateau
g) P’ateau is also called	vii) a dissected plateau
h) Decan plateau is a	viii) grow in the mountains
i) Darjeeling is a famous	ix) ‘Roof of the world’
j) Forests of valuable soft wood trees	x) continental plateau

Answer:
a) Prairries in North America-one of the famous plains of the world.
b) The Tibet plateau is3655 m high.
c) The Chhotanagpur plateau is a dissected plateau.
d) Pamir plateau is known as ‘Roof of the world’.
e) Indo-Ganga-Brahmaputra plains is an alluvial plains.
f) Antertica is a continental plateau.
g) Plateau is also called a table land.
h) Decan plateau is a lava plateau.
i) Darjeeling is a famous mountainous tourist spot.
j) Forests of valuable soft wood trees grow in the mountains.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What is landform?
Answer:
The diversity of land is called landform.

Question 2.
What are the different forces that are responsib ce for creation of landform.
Answer:
The two different forces that are responsible for creation of landform are endogentic foree and exogenatic force.

Question 3.
What is the heighest plateau of the world?
Answer:
The heighest plateau of the world is Pamir plateau.

Question 4.
What is mountain?
Answer:
Mountain is expansive, rocky landform that is generally higher than 900 m.

Question 5.
Name a young fold mountain of India.
Answer:
A young fold mountain of India is Himalaya.

Question 6.
What is Mountain Knot?
Answer:
When a few mountains chains meet in a highland is called mountain knot.

Question 7.
What are peaks?
Answer:
The narrow, pointed summits of the mountains are called peaks.

Question 8.
What are Mountain Range?
Answer:
Numerous vaiieys and peaks located over a vast stretch forms a mountain range.

Question 9.
What is valley?
Answer:
Lowland between two high ridges is called valley.

Question 10.
What are the different types of mountain according to their origin?
Answer:
According to their origin mountains are of three types-fold mountain, block mountain and volcanic mountain.

Question 11.
What is volcanic mountain?
Answer:
At the time of volcanoic erruption the ash, lava boulders come out and formed the mount{ }^{-in which is called volcanoic mountain.

Question 12.
What is mountain Chain?
Answer:
Wlren mountain peaks and valleys extended laterally is called mountain Chain.

Question 13.
What is plateau?
Answer:
A landform that suddenly rises over its surroundings with steep slopes on all sides, ge ierally over300 m high, is called a plateau.

Question 14.
Why is peateau called ‘Table land’?
Answer:
The top of the plateau is almost flat and table like. So It is called ‘Table land.’

Question 15.
What is the highest plateau of India.
Answer:
The highest plateau of India is Ladak Plateau.

Question 16.
What is Lava plalteau”?
Answer:
At the time of volcaoic erruption lava comes out and forms plateau which is called lava plateau.

Question 17.
What is Intermontane plateau?
Answer:
The p!ateau which is surrounded by the mountains is called intermontane pleteau.

Question 18.
What is What is the world’s highest plateau?
Answer:
Pamir Plateau is the highest plateau of the world.

Question 19.
What is plane?
Answer:
A plain is a low, flat stretch of land.

Question 20.
How lava plains are created?
Answer:
Lava plains are formed when lava accumulates over vast, flat, low lying stretches.

Question 21.
Give two examples of fold mountains.
Answer:
Himalayas in Asia and Andes in South America are two fold mountains.

Question 22.
Give two examples of block mountains.
Answer:
Satpura in India and Black Forest in Germany are two block mountains.

Question 23.
Give two examples of volcanic mountains.
Answer:
Vesuvias in Italy and Fujiyama in Japan are two volcanic mountains.

Question 24.
Give an example of dissected plateaus.
Answer:
Chhotanagpur plateau is a dissected plateati.

Question 25.
Give two examples of continental plateaus.
Answer:
Antarctica and Greenland are two continental plateaus.

Question 26.
What kind of plateau is Chhotanagpur plateau?
Answer:
Chhotanagpur plateau is a dissected plateau.

Question 27.
Name two famous plains of the world.
Answer:
Gangetic plains of Asia and Pampas of South America are two famous plains of the world.

Question 28.
What is the other name of lava plateau?
Answer:
Lava Plateau is also known as volcanic plateau.

Short Questions & Answers : (2 marks for each question)

Question 1.
What is endogenetic and exogenetic force?
Answer:
The force that generates in the interior of the Earth is known as endogenetic force.
Example: Earth movement force.
The outer force of the Earth’s surface is known as exogenetic force.
Example: river, wind, glacier etc.

Question 2.
What is mountain? What is mountain peak?
Answer:
Very high (900 m and above) and very extensive land mass is called mountain. Example: Himalaya

Question 3.
The conical narrow upper portion of the mountain is called peak. Example: Mount Everest. 3. What is fold mountain.
Answer:
The mountain that is formed by the pressure of the plates of two sides to the layer of the silt accumulated under the sea is called fold mountain. Example: The Himalaya of India. Andes of South America and Rocky in North America.

Question 4.
What is Block mountain?
Answer:
Cracks are created due to the earth’s movement. The middle portion of the cracks sometimes uplifts or goes down creating mountain which is called Block mountain.
Example: Satpura in India, Vosges in France and Black forest in Germany etc.

Long Questions & Answers : (3 marks for each question)

Question 1.
How are fold mountains created? Give an example.
Answer:
Fold mountains are created when two plates move together. This can be where two continental plates move towards each other or a continental and an oceanic plate. The movement of the two plates forces sedimentary rocks upwards into a series of folds.

Example: At the place of the Himalaya Mountain there was a geosyncline almost 10 crore years ago. The name of the land to its north was Angara land and to the south was gondowana land. For many years the silt, brought by the rivers of these two land was accumulated at the bed of Tethes. Due to the downward pressure of the layers of the silt the bed of Tethis went downword and the two land came closer. For this reasen the fold occured on the silt and it uplifted to form a mountain. As the fold mountain is originated from geosyncline the bredth of the mountain is lesser than the length of the mountain.

Question 2.
What is valcanic Mountain?
Answer:
Hot molten magma remains in the earth chamber. For earth’s movement or only other causes the hot molten magma expands. At that time due to changing of earth’s movement the magma comes out through any openings of the earth’s surface and deposits around the cracks to form volcanic mountain. Due to the course of time it becomes conical in shape. This is called valcanoic mountain.

The example of the volcanic mountains are Etna in Sicily, Visuvius in Italy, Kilimanjaro in Africa, Fujiyama in Japan etc. But the Guaiyati in Chilly is he highest(19.082 \mathrm{Ft})$ active volcanic mountain of the world.

Question 3.
Classify the volcanie mountain according to their shape and structure.
Answer:
According to the shape and structure the volcanic mountains are classified into four categories-i) Volcanic mountain with conical shape, ii) Volcanic mountain with dome shape, iii) Valeanic mountain with explossive crater, iv) Volcanic Mountain with composite conical.
i) Volcanic mountain with conical shape : This is formed by large explosion. It looks like cone, This type of volcano is found in Japan.
ii) Volcanic mountain with dome shape : Due to large explosion the thick magma comes out form dome shaped Volcano. This types of volcano is found in Hawai island.
iii) Volcanie mountain with explossive crater : This type of volcano is formed due to large explosion by making big crater. This type of volcanic mountain is found in lceland.
iv) Composit volcanic mountain with conical shape : When explosion countinues for long time a main erativ forms with other earths surrounded it. This type of Valcano is found in Maxico.

Question 4.
Classify Plateaus according to their origin.
Answer:
According to their origin plateaus are classified into three categories-i) Dissected plateau, ii) Intermontane plateau, iii) Lava plateau
i. Causes for the origin of dissected plateau : Sometimes the old fold mountain is eroded by the natural forces for long time to form high plateau: When the soft rocks of the high mountain eroded or brought away by the wind or river water leaving the hard rocks only as the peak of the mountain then it is called Residual plateau. The Residual plateau is sometimes dissected by narow river vally, it is called dissected plateau. The example of dissected plateaus are Bindhya plateau in India, Highland of Scottland etc.

ii. Cause for the origin of Intermontane plateaus: At the time of the formation of fold mountain the places comperatively lower uplifted to form plateaus for the earthquake. This type of plateaus are generally surrounded by the mountains. This is called inter mountaine plateau. The example of intermontane plateaus are the Tibetan plateau, Iranian plateau etc.

iii. Cause for the origin of volcanic plateaus: The lava plateau is made up with bassalt rock. The hot molten lava comes out through the openings of the earth surface and begines to accumulate to the earths surface. In due course of the time the lava cools down and hardens to form plateau. This types of plateau froms due to the accumulation of lava. Thus it is called lava plateau or volcanic plateau or depositional plateau. The example of this type of plateau in the Decan plateau in India, the Somalian and Etheopian plateau, the Puner plateau in Argentina.

Question 5.
Classify the plain according to their origin.
Answer:
According the their origin plains are classified mainly into two categories-

1. Plain of accumulation
2. Plain created by earths movement.

1. The classification of plain of accumulation : The plain of accumulation is also devided into 8 categories-

1. alluvial plain
2. flood plain
3. deltaic plain
4. coastal plain
5. lake plain
6. Lava plain
7. Glacier plain
8. loess plain

2. Plain created by earth movement : This type of plain is classified into two categories

1. uplifted and
2. downward plain.

Question 6.
Write the causes for the formation of different plains.
Answer:
i) The silt accumulated under the rivers, seas and lakes to form alluvial plain (genstic plain), ii) For the volcanic erruption of the volcano (lava plain-northen part of the Decan), iii) the plain formed by the glacier (Prairries in North America), iv) In desert region the sand blown by the wind and deposited to form plain (Loess plain in china), v) The low hills and plateau eroded to form plain (some part of the Ranchi plateau), vi) For earthquake high land goes downward to form plain (Taranian plain) or uplifted to form plain (Karamandal coast in India).

Question 7.
Write the influence of Mountains in the human life.
Answer:
Very high (900 m and above) and very extensive landmass is known as mountain. It has influence in human life-

1. The mountain has an important role in originating rivers and streams.
2. It regulates the climate.
3. The facilities of livelihood are less in this region.
4. Lack of population in this region.
5. Agriculture, industry could not be flourished in mountain region.
6. Mountain helps to grow tourism.
7. The people of the mountain region are hard and active.

Question 8.
Mention the influence of plateau in human life.
Answer:
The influences of plateau in humans life are–

1. Agriculture is not suitables in rocky plateau region.
2. The rivers of the plateau are suitable for generating hydroelectric power.
3. There is lack population in this region.
4. The pleasant weather of plateau is fit for tourism.
5. Sufficient minerals are formd in the plateau region.
6. The communication system is not so developed.

Question 9.
Write the influences of plain in human life.
Answer:
The influences of plain in human life are-

1. The alluvial soil is fentile and suitable of agriculture.
2. The pondlable water is avilable in plain.
3. The life of the people of plain is easy and comfortable.
4. Due to the facility of life is more, the people are lazy and weak.
5. The communication system is highly developed.
6. Riverine civilization has been flourished in the plain.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 3 Air Pressure offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 3 Question Answer – Air Pressure

Multiple Choice Questions & Answers : ( 1 mark for each question)

Question 1.
Which is false, air is-
i) colourless
ii) odorless
iii) volumeless
Answer:
iii) volumeless

Question 2.
Which is false, molecules are visible in-
i) solid
ii) gas
iii) liquid
Answer:
ii) gas

Question 3.
With the increase of altitude the air pressure and temperature –
i) decreases
ii) increases
iii) remains same
iv) may increase or decrease
Answer:
i) decreases

Question 4.
The air pressure in equitorial and tropical regions are –
i) medium
ii) low
iii) high
iv) may be high or low
Answer:
ii) low

Question 5.
High pressure areas usually experience the weather-
i) cloudy
ii) rainy
iii) stormy
iv) calm
Answer:
iv) calm

Question 6.
Example of a violent fast wind-
i) syclone
ii) hurricane
iii) typhoons
iv) all the winds
Answer:
iv) all the winds

Question 7.
Low pressure areas usually experience the weather-
i) stormy
ii) clear sky
iii) calm
Answer:
i) stormy

Question 8.
The imaginary line which connect equal pressure region in weather map is known as –
i) isobar
ii) isotherm
Answer:
i) isobar.

Question 9.
The region where temperature remain high, there prevails-
i) high pressure
ii) low pressure
Answer:
low pressure.

Question 10.
Moist air is-
i) lighter
ii) heaver than dry air
Answer:
lighter

Fill in the blanks : (I mark for each question)

1. The hight of the Mount Everest is ________.
Answer:
8848m.

2. The air pressure is almost per ________ square centimeter.
Answer:
1 kg.

3. ________is an important factor to determine the weather and in our day to day life.
Answer:
Air pressure.

4. Air pressure ________ with the increasing of altitude.
Answer:
reduces.

5. The air exerts pressure to ________ derection.
Answer:
all.

6. ________ is used for measuring air presure.
Answer:
Barometer.

7. The density of air ________ with the increasing of altitude.
Answer:
decreases.

8. The air gets heated by ________ process.
Answer:
three.

9. In the cooler region of Earth’s surface ________ pressure prevails.
Answer:
high.

10. Water vapour remains very ________ in cooled and heavy air.
Answer:
low.

11. Isober expressed in ________.
Answer:
Milibar.

12. Volume of air changes with the ________.
Answer:
change of temperature.

13. Moist air is ________ than dry air.
Answer:
lighter.

14. Air pressure is maximum on ________ of the earth.
Answer:
sea surface.

15. Low pressure generate around equator and high pressure in both the ________.
Answer:
tropics.

State whether True or False : ( 1 mark for each question)

1. Air has mass and volume.
Answer:
true

2. The air pressure per square foot is about weight of one tonne of material.
Answer:
true

3. Molecules in solid and liquid are not visible.
Answer:
false

4. Air pressure is very significant in our daily lives.
Answer:
true

5. Air pressure at sea level is equal to that of a 72 cm column of mercury.
Answer:
false

6. Moister-laden air is heavier than dry air.
Answer:
false

7. Warm air expands and starts to move upwards. is
Answer:
true

8. Isobar represent air pressure meacured in milibars. is
Answer:
true

9. High pressure areas usually experience cloudy weather.
Answer:
false

10. Air in low pressure area is usually light and expanding.
Answer:
true

11. Air flows from high pressure to those of low pressure.
Answer:
true

12. The The instrument used to measure air pressure is called Barometer.
Answer:
true

Match the column A with column B.

Column A	Column B
a) There is some air	i) low air pressure
b) Molecles in solid	ii) heavier
c) There is no air	iii) towards the surface of the earth
d) Boiling point of water drops	iv) are visible
e) Turbulent weather is a result of	v) weather in low pressure areas
f) Cold polar regions have	vi) in our body
g) Dry air is	vii) higher air pressure
h) We have cloudy, stormy	viii) in the space
i) Cloud and heavy air sinks	ix) in mountanious regions

Answer:
a) There is some air in our body.
b) Molecles in solid are visible.
c) There is no air in the space.
d) Boiling point of water drops in mountanious regions.
e) Turbulent weather is a result of low air pressure.
f) Cold polar regions have higher air pressure.
g) Dry air is heavier.
h) We have cloudy, stormy weather in low pressure areas.
i) Cloud and heavy air sinks towards the surface of the earth.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
How much presure does air exert per square ft ?
Answer:
Air exerts the pressure of 1 tonne per square ft.

Question 2.
Why is the space suit of astronauts filled with air.
Answer:
There is no air in space. So to keep the balance in pressure between internal air pressure and the outer air the spacc suit of astronaut filled with air.

Question 3.
Why is the air pressure maximum on sea surface?
Answer:
The air pressure is maximum on sea surface because the gravitational pull is maximum in sea surface.

Question 4.
What is the air pressence of sea surface?
Answer:
The air pressure on sea surface is 101325 ml.

Question 5.
Who discovered the mercury Barometer?
Answer:
The scientist Torricelli discoming the mercury Barometer.

Question 6.
How does the mercury level react if the pressure increases?
Answer:
If the pressure increase the mercury level also increases.

Question 7.
How does the air pressure vary with the increasing of every 110 altitude.
Answer:
With the increasing of every 110 m altitude to the air pressure reduces equal to 1 cm mercury level.

Question 8.
What is isobar?
Answer:
The imaginery line which connect equal pressure region in weather map is known as isobar.

Question 9.
Where is the rotational speed is maximum on the Earth?
Answer:
The rotational speed is maximum in and around equator.

Question 10.
Why there are problems of boiling of cooking anticles in high altitude?
Answer:
In high altitude the boiling point is less then 100° C that causes problems of boiling of cooking articles in high altitude.

Question 11.
Why does the astronauts carry oxygen cylinders with them?
Answer:
At high altitudes air with oxygen becomes scarce, so astronauts carry oxygen cylinders with them.

Question 12.
Which air is lighter-moister-laden or dry air?
Answer:
Moister-laden air is lighter than dry air.

Question 13.
Where is the speed of earth’s rotation highest?
Answer:
The speed of earth’s rotation is highest at the equator.

Question 14.
Where does stormy and turbulent weather prevail?
Answer:
Stormy and cloudy weather prevails in low pressure areas.

Question 15.
What kind of air is formed in a high pressure area?
Answer:
In a high pressure area air is sold and compact..

Short Questions & Answers : (2 marks for each question)

Question 1.
What is air pressure? How can it be clasiffied.
Answer:
In certain place on the earth surface the layers of air exerts pressure per square centimeter which is known as air pressure. There are two types of air pressure high pressure and low pressure.

Question 2.
Why do we not feel the air pressure.
Answer:
In spite of living in water the fish can not feel the pressure of water. Similarly in spite of living in the lowest layer of air we can not feel the air pressure. This is because our body pressure and the atmospheric prerssure is equal.

Question 3.
The air exerts pressure-Prove it with an experiment.
Answer:
Take a glass full of water and place a post card to cover the glass. Now if we turn over the glass we see the post card sets firmly on the glass and water remain as it. It proves that the air exerts pressure over the post card in upward direction.

Question 4.
What are high pressure and low pressure region?
Answer:
In which places the air pressure is more than that of surrounding area is called high pressure region. On the orther hand in which places the air pressure is lesser than that of surrounding areas is called low pressure region.

Question 5.
What will be the weather of two places? If you travel from the Puri beach to Mount Everest, what types of changes in your daily life are likely to happen?
Answer:
As the Mount everest is higher than the sea level the temperature is lesser than Puri. Thus the climate of Mount Everest is very cold if we travel from Puri to Mount Everest we have to use wollen cloths due to the cold climate.

Question 6.
What is the cause of variation in air presure.
Answer:
Circulation of air in the atmosphere is caused by pressure differences generated primarily by uneven isolation Air flows from areas higher pressure to areas of lower pressure.

Question 7.
What is the normal range for air pressure?
Answer:
A metric unit has been defined to describe normal atmospheric pressure, called a bar, and the instrument become a barometer. Normal average sea-level pressure is 1.o1325 bars.

Long Questions & Answers : (3 marks for each question)

Question 1.
What is isobar? What are its characteristics?
Answer:
Isobar is the imaginary line which connects equal pressure region in weather map. The characteristics of isobar are-

1. The unit in which isobar is expressed is milibar. The normal air pressure over the Earth varries from 980 to 1050 ml.
2. It is expressed according to the presure on sea level.
3. They never intersects or touch one another.
4. The difference of air pressane is maximum when the lines of isobars are very closed to each other.

Question 2.
What are the characteristics of high presure.
Answer:
The characteristics of this high pressure are:

1. The high pressure is created when the temperature of air islow. Thus the high pressure prevails mountain region and cold polar region.
2. For being cold the air of high pressure region is compressed.
3. High pressure develops due to the decending nature of air. Thus cold air goes down in the cold region, the denisity of air increases and pressure also increases.
4. The water vapour present in cool and heavy air is very low. That is why the cloud, rain etc are not occured in high pressure rigion.

Question 3.
What are the characteristics of low pressure.
Answer:
The characteristics of low prresure are-

1. The low pressure creates for the increasing of the temperature of air. Low pressure is found in Equoatorial and tropical region.
2. The air in low pressure region is light and expanded.
3. In the hot region the air on the earth’s surface gets heated and rises up. Thus the density of air near the earth surface decreases and the air pressure also decreases.
4. The water vapour in hot air condensed into water droped or ice when the air comes contact of cold air at upper layer. So the cloud formation, rain storm and rough weather occured in low pressure area.

Question 4.
What are the causes for the variation of air pressure.
Answer:
The causes for the variation of air pressure are-
i. The amount of water yapour in air: The water vapour is lighter than dry air. So the water vapour containing air is lighter and exerts less pressure than dry air. This is why in rainy season the air pressure decreases than in summer.

ii. The temperature of air: Like other substance the air expands in getting heated and the density of air decreases. Then the air becomes lighter. The light air exerts less pressure and the capasity of holding water vapour increases when the air becomes hot. So at the places where waer bodies are more the air becomes wet and exerts less pressure. On the other hand the capasity holding air of cold air is less, thus it exerts more pressure. Therefore the air pressure is more in winter than in summer.

iii. The altidude: The air has many layers. The layers lie one above another. So the upper atmospheric layers exerts force on the lowest level that lies closest to the earth surface. So the density of the level is meny high and the density is gradually decreased with the altitude. The weight of the air with low density is lesser and thus. it exerts less pressure. So as proceed to the high altitude from the sea level the air pressure decreases.

iv. The depth of the atmosphere: The air pressure varies due to the variation of the depth of atmosphere. The 90% eliment of the atmosphere are present within 16 km from the earth surface. So the depth of the atmosphere that prevails on the sea level is not present on high mountain. So the depth of the air and atmospheric pressure decreases with the altitude.

Question 5.
Describe the different pressure belt of Earth.
Answer:
The temperature of the air in different places is determined by the angle in which the sunrays fall on the earth. According to the different temperature of this air the Earth is divided into different pressure belt. But the pressure belts shift a little with the season change. The differnce of air pressure causes the wind blows. There are two types of air pressure.
i) High pressure and low pressure: According to air pressure the Earth is devided into seven permanent pressure belt. They are as fallows :

ii) Equatorial low pressure belt : The sun rays fall directly on the both side of the equator between 5°-10°north and south. The air of this region is hot and light. On the other hand the water body is more than the land mass here. This waters body gets healed by the tremendous heat of the sun and the water vapour rises up and mixes with to air. Thirdly – due to the rotation of the earth the air of the region gets deflected to the north and south. Thus this region is the most powerful low pressure belt.

iii) Sub tropical high pressure belt: This pressure belt lie to the both side of tropic of cancer and in the northern hamisphere and to the both side of tropic of capricorn in southern himsphere. The hot air of equatorial region rises up an gets cool there. Then its became heavy and came down to this two tropical region resulting high pressure belt.

iv) and (v) Polar high pressure belt: The speed of rotation of the Earth is minimum near the pole. Besides dwtethis. Slanting sun rays the water vapour is less in this region. The day and night’s one with a span of six months. Therefore the region remains ice capped through out the year. The density of the air is high that creats high pressure belt.

vi) and (vii) : Sub polar low pressure belt : At 60°-65° latitude of two hemisphere the low pressure belt is created due to the deflectic of the air.

Additional Questions and answers :

Question 1.
Write the characteristics of high pressure.
Answer:

1. Places with lower temperature, like the cold temperate and polar regions, have high air pressure.
2. Air in a high pressure area is usually cold and compacted.
3. Cold and heavy air naturally sinks towards the surface of the earth, gets denser and exerts higher pressure.
4. Cold and dense air is generally dry. So high pressure areas usually do not experience cloudy or rainy weather. Calm weather and clear sky prevail here.

Question 2.
Write the characteristics of low pressure.
Answer:

1. Places with higher temperature, like the equatorial and tropical regions, have low air pressure.
2. Air in a low pressure area is usually light and expanding.
3. In warm areas, air near the surface of the earth gets heated and becomes light. Thus it rises and the ascent of air creates low pressure.
4. The water vapour in hot air is condensed as the air cools down in high altitude. Hence water droplets or snow/ ice is formed. This is why we have cloudy, rainy, stormy and turbulent weather in low pressure areas.

Question 3.
What is the cause of flow of air?
Answer:
Air flows from areas of high pressure to those of low pressure. This proves that the difference in pressure between two areas is mainly responsible for the flow of air between them. Also, it is this flow that helps in maintaining the balance between high and low pressure zones on the earth’s surface. The more is the pressure difference, i.e. the lower the air pressure in the low pressure zones, the more is the speed of the wind blowing into that zone from the surrounding high pressure areas to keep up the balance of air pressure. When devastation is caused to life and property by violent fast winds, then those winds are known as cyclones, typhoons, hurricanes, tornadoes etc.

Question 4.
Write the causes of variation of air temperature.
Answer:
Volume and density of air change with changes in temperature. The air molecules get activated by heat and start moving apart. Thus, warm air expands, gets lighter and starts to move upwards. Its density is also reduced. So the number of molecules in a specific volume of air is also reduced. This reduces air pressure. When air cools down, it shrinks and its density increases. This increases air pressure. This is why the cold polar regions have higher air pressure but the hot equatorial region has low air pressure.

Gravity and pressure of overlying air lead to greater density and therefore, greater pressure of air near the earth’s surface. These molecules disperse with altitude and the air becomes gradually less dense and exerts less pressure. This is the reason why the boiling point of water drops in mountainous regions. That is, water starts boiling at a temperature below 100° C when the air pressure drops.

Moisture-laden air is lighter than dry air. So, it exerts less pressure. Rainy, stormy, turbulent weather is actually a result of the low air pressure that is generated by moisture-laden air. Dry air is heavier and leads to the formation of high air pressure condition.

Question 5.
Is air pressure the same everywhere?
Answer:
Air pressure is maximum at the sea level on the surface of the earth. Gravitational pull and the great pressure of overlying air bring the molecules of air closer to each other. So the density and air pressure increase. As altitude increases, the molecules of air are spaced apart and the density decreases. Thus, the air pressure and temperature decreases with the increase of attitude.

Question 6.
Why don’t we feel the the air pressure?
Answer:
There is some air inside our body. That is also axerting equal and opposite pressure to that of the outer air on the surface of oyr body. This is why we do not feel the pressure.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 2 Determination of the Location of a Place on the Earth’s Surface offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 2 Question Answer – Determination of the Location of a Place on the Earth’s Surface

Let’s have some fun (Page no. 20)

Funny Game (Page- 23)

(Page-25)

Brainware

Do we experience day and night at the same time on the same parallel? if not, why?
Answer:
Day and night do not happen in same time on same parallel because the Earth is sperical. So the sunrise and sun set do not occur at the same time through out the Earth.

How can you determine the location of a place between two parallels?
Answer:
To determine the location of a place between two parallel we should measure the angle that forms from the place to the centre of the Earth along the equatorial plane.

Where can you see eastern and western hemispheres simultaneously?
Answer:
We can observe eastern and western hemisphere from the Astronomical observatory in Greenwich.

Intution (Page- 27)

Compare and contrast between parallels of latitude and Meridians of longitude.
Answer:
The difference between parallels and Meridians of longitude are as follows.

1. The cercumference of different parallels are different.	1. The circumference of different Meridian are same.
2. Highèst latitude vảlues $90^{\circ}$	2. Higliest fogitude values 180°
3. Parailels stretch from east to west.	3. Meridian Stretch from West to east.
4. They are full circle.	4. They are half circle.

Why is the time same on the same meridian?
Answer:
As the meridians stretch from north to south of the earth the sunrise and sunset at the different place on same meridians occur at the same time. So the local time of those places are same. The rotation of the Earth from west to east. On its axis is responsible for that.

On which direction of the earth, does the time increase and why?
Answer:
When the Earth goes to east the time is increased on the sun rises at the east. first. It is because the Earth rotates from west to east.

Live telecast of the inauguration of London Olympic was seen at 11.30 p.m. in India. When did the programme start in London?
Answer:
The time of 82° 30′ meridian is considered as the standard time of India. The difference of time between India and.Greenivich is 5 hours 30 m : India is located to the east of London. To the Indian time is increased by 5 . h .30 m, If the in auguration of London olympic was 11.30 p.m. in India the programne started in London (11.30.p.m -5 h 30 m) = 6 p.m.

How do you determine the location of a place on the earth’s surface with suitable diagram.
Answer:
With the help of parallels and meridians inter-sect each other and make a grad system. The inter secting points help to determine the location of a place.

If the lalitude of a place is 40° N and latitude is 80° E. it is understood that the place fies to 40°. North from equator and 80° east from Prime meridian. So the place is situated the intersecting point of 40° N latitude and 80° e longitude.

Class 7 Geography Chapter 2 Question Answer West Bengal Board – Determination of the Location of a Place on the Earth’s Surface

Multiple Choice Questions & Answers (1 mark for each question).

Question 1.
Equator’s value is-
i) 90°
ii) 30°
iii) 60°
iv) 0°
Answer:
iv) 0°

Question 2.
The fatitudinal location of Kolkata is-
i) 34° 22′ N
ii) 22° 34′ S
iii) 22° 34′ N
iv) 22° 34′ S
Answer:
iii) 22° 34′ N

Question 3.
The highess value of longitude is –
i) 180°
ii) 90°
iii) 60°
iv) 30°
Answer:
i) 180°

Question 4.
Estimated latitude of ‘Tokyo is-
i) 30° N
ii) 35° N
iii) 20° N
iv) 32°
Answer:
ii) 35° N

Question 5.
The longitude of New Delhi-
i) 70° 13′ E
ii) 77° 13: E
iii) 67° 18′ E
iv) 77° 13′ W
Ans:
ii) 77° 13′ E

Question 6.
The latítude of New Delhi-
i) 28° 38′ N
ii) 20′ 30′ x
iii) 28′ 38′ S
iv) 25° 30′ N
Answer:
i) 28 38′ N

Question 7.
The standard time of India is considered as –
i) 82° 32′
ii) 84° 30′
iii) 88° 30′
iii) 80° 20′
Answer:
i) 82° 30′

Question 8.
The libes of longitudes to each other are –
i) parallel
ii) not parallel
iii) full circle
Answer:
ii) nof parallel

Question 9.
The total number of meridians are-
i) 179
ii) 180
iii) 120
iv) 360
Answer:
iv) 360

Question 10.
If we go further east then the time will be-
i) the same
ii) increased
ii) decreased
Answer:
ii) Increased:

Question 11.
The latitude of the north pole is-
i) 90° N
ii) 90° S
iii) 61 \(\frac{1}{2}\) ° N
iii) 61 \(\frac{1}{2}\) ° S
Ans :
i) 90° N.

Question 12.
The greatest latitute of the Earth is-
i) the Tropic of Capricon
ii) the Tropic of cancer
iii) the Equator
Answer:
iii) the Equator.

Question 13.
The latitude of Nasik in Maharastra is –
i) 24° S
ii) 24° N
iii) 20° S
iv) 20° N
Answer:
iv) 20° N

Question 14.
The valie of the meridian just opposite to the Prime meridian is-
i) 90°
ii) 180°
iii) 360°
iv) 120°
Answer:
ii) 180°

Question 15.
The other name of the Equator is-
i) Tropic of cance
ii) Great circle
iii) Tropic of capricon
Answer:
ii) Great Circle

Question 16.
The value of the Tropic of cancer is –
i) 0°
ii) 23 \(\frac{1}{2}\) ° N
iii) 23 \(\frac{1}{2}\) ° S
Answer:
iii) 23 \(\frac{1}{2}\) ° S

State whether True or False : (1 mark for each question),

1. Meridians are not parallel to each other.
Answer:
True

2. Distance between two mertdians is maximum at the poles.
Answer:
False

3. Meridians are semi-circular.
Answer:
True

4. Among the parallels of latitude value of equator is 90°.
Answer:
False

5. 90° North latitude is North pole.
Answer:
True

6. Parallels of latitude are parallel to each other.
Answer:
True

7.
The difference between Indian Standard Time and greenwich Mean time is 2 hours 30 minutes.
Answer:
False

8. When it is afternoon in London, it is night in India.
Answer:
True

9. When the sun remains just overhead of a meridian, the time will be 1 pm.
Answer:
False

10. The eart takes 4 minutes to cover 1°.
Answer:
True

Fili in the blauks : (1 mark for each question)

1. 0° line of latifinde is known as _____.
Answer:
Equator.

2. The Ritme Menidiad passes through the _____.
Answer:
‘Rayal Greenwich.

3. The _____ devided the Earth into eastern and Western pemisphere.
Answer:
Prime Meridian.

4. The lines of Latitudes are _____.
Answer:
Full circle.

5. The north pole and south pole are connected by _____.
Answer:
The lives of longitude.

6. The Earth takes _____ minutes to rotate 1° meridian.
Answer:
4 .

7. To ditermine the latitude and longitude of a place on earth a modern measure is _____.
Answer:
GPS or Global positioning system.

8. _____ meridian is considered as the standard Meridian in India.
Answer:
82° 30’ E.

9. Meridians are the _____ in shape or nature.
Answer:
Half.

10. Lines of Latitudes are _____ to each otber.
Answer:
Parallel.

11. The value of parallels gradualyy _____ towards pole.
Answer:
Iincreases.

12. _____ is kinown as Great Circle.
Answer:
Equator.

13. Presently GPS System is attached to car and _____.
Answer:
mobile phone

14. Determination of time of a place according to meridian is called _____.
Answer:
Local Time

15. Meridians are not _____ to each other.
Ans :
parallel.

Match the column A with columin B

Column A	Column B
a) Latitudes are parallel	i) are called parallels of tatiturie
b) 90°North latitude	ii) is located at Greenwich
c) Globe is a miniature replica	iii) side of Greemwich
d) Horizontal lines parallel to the equitor	iv) seuni-circular
e) Kolkata is located	v) is North pole
f) Merdians are	vi) are 90°N and 90°S
g) Distance between two meridians	vii) to each other
h) The Royal Astronomical Observatory	viii) on the 22°34‘ N parallel
i) India is on the eastern	ix) is maximum at the Equator
j) The latitude of the two poles	x) of the earth

Answer:
a) Latitudes are parallel to each other.
b) 90° North latitude is North pole.
c) Globe is a miniature replica of the earth.
d) Horizontal lines parallel to the equitor are called parallèls of latitude:
e) Kolkata is located on the 22°-34′ N parallel.
f) Merdians are semi-circular.
g) Distance betweer two meridians is maximum at the Equatof.
h) The Royal Astronomical Observatory is located-at Greenwich.
i) India is on the eastern side of Greenwich.
j) The latitude of the two potes are 90 N N aird 90° S.

Very Short Questions & Answers : (1 márk for each question)

Question 1.
What is- the time equavalent for 1 degree of longitude?
Answer:
If you move from one longitude to the next the difference will be of 4 minutes.

Question 2.
What is GPS ?
Answer:
GPS is Global Positioning System which is a modern measure to determine the latitude or-longitude of a place.

Question 3.
What is the value of North pole and South pole?
Answer:
Tlie value of North pole is 90° North and South pole is 90° South.

Question 4.
Which line devides the Earth in Northern and Southern hemisphere?
Answer:
The Equator devides the Earth in Northern and Southern himisphere.

Question 5.
What is latitude?
Answer:
Latitude is a geographical coordinates that specifies north south position on earth surface.

Question 6.
What is longitudes?
Answer :
Longitude is a geographical; coordinates which specifies east west position on earth surface.

Question 7.
What is the line of Latitude?
Answer:
The imagirary lines that sarround the Earth from East to West is called line of latitude.

Question 8.
What is the line of longitude?
Answer:
The imaginary balf circles that connects the north pole and south pole is known as the lines of longitude.

Question 9.
What is the value of the lines of latitudes?
Answer:
There are 180 lines of latitude, from 0° to 90° to the north of the Equator and 0° to 90° to the Sorth of the Equator:

Question 10.
How many lines of longitude are there?
Answer:
There are 360 lines of longitudes.

Question 11.
What is the name of the line of longitude which lies just opposite of Prime mẹidian?
Answer:
The line of longitude that lies just opposite of prime Meridian is 180° lines of latitude.

Question 12.
The time of which place of India is considered as the standard time of India.
Answer:
The time of Alahabad is considered as the Standard time of India.

Question 13.
On which city the Prime Meridian passes through?
Answer:
The Prime Meridian passes through the city of Greenwich near London.

Question 14.
Why the equator is called the great circle.
Answer:
The diameter of Equator is the greatest so it is called the great circle.

Question 15.
What is the angular value of the circumference of the Earth.
Answer:
The angular value of the circumference of the Earth is 360°.

Question 16.
How much time the Earth takes to complete 15° angle?
Answer:
The Earth takes 1 hour to complete 15° angle.

Question 17.
What is G.M.T.
Answer:
G. M. T. is Greenwich Mean Time.

Question 18.
What is East Meridians.
Answer:
Meridians, that are situated in the east of Prime Meridian are called the East Meridians.

Question 19.
What is West Meredian?
Answer:
Meridions, that are situated in West of Prime Meridian are called the West Meridians

Question 20.
What is local time?
Answer:
Determination of time of a place according to meridian is called local time.

Short Questions & Answers : (2 marks for each question)

Question 1.
How are the hemispheres divided ?
Answer:
There are generally considered to be four hemispheres: Northern, Southern, Eastern and Western. The Equator or line of 0 degrees latitude, divides the earth into the Northern and Southern hemisphere. Prime meridian divides the earth into the Eastern and Western hemisphere.

Question 2.
How can you determine the exact location of a place?
Answer:
Absolute location describes the location of a place based on a fixed point on earth. The most common way is to identify the location using coordinates such as latitude and longitude. lines of latitude and longitude crisscross the earth.

Question 3.
Write two characteristics of the parallels of laitude.
Answer:
1. They are parallel to each other.
2. Their circumference gradually reduces towards th poles.

Question 4.
Write two characteristics of the meridians of longitude.
Answer:
1. Meridians are semi-circular.
2. Each meridian of longitude merges at the North and South pole.

Question 5.
Why is the Standard Time impentant?
Answer:
The different times of different places results problems in the work of Post office, railways and Broad casting. So the local time of any places of a country is considered as the standard time.

Question 6.
What do you understand by the words that the meridian of Kolkata is 88° 30′ \mathbf{E ?
Answer:
The meridian of Kolkata is 88° 30′ E means Kolkata lies at Eastern hemisphere. The straight line that connect Kolkata and the centre of the Earth forms an angle with the value of 88° 3′.

Question 7.
What is GPS?
Answer:
GPS or gloos Pationing system the a modern measure to determine the latitude and longitude of a place. It is applied from the artificial sattelite of the Earth. Now it is present in modern ship, arroplane, car even in mobile phone.

Long Questions & Answers : (3 marks for each question)

Question 1.
State the characteristics of lines of latitude.
Answer:
The characteristics of lines of latitude are as follows :
a) The lines are parallel to each other.
b) Towards the pole the circumference of latitude gradually decreases.
c) Towards the pole the value of parallels gradually increases.
d) Amongst all the parallels, Equator is an important one and it is known as Great Circle. The value of Equator is 0°.
e) 89 parallels can be drawn in each hemisphere considering 1° interval. So there are 178 parallels. The poles are nothing but two points only.

Question 2.
State the charecteristics of the lines of longitude.
Answer:
The charecteristics of lines of longitude are as follows :
a) The Meridians does not run paralles to each other.
b) The distance between two meridians decreases towards poles and increases towords equator.
c) Towards east or west of the prime Meridian, the value of meridians gradually increases. There are 179 merians in the east and are 180° meridian (International Date line). All total there are 360 meridians.
d) In shape or nature meridians are half circle in shape.

Question 3.
What do you mean by local Time and standard time?
Answer:
When sun remains just over the head of a place the time will be 12 noon of that place, According to this time the other time of the day is determined this is called Local Time. When the different meredian pass through a country then any one of the meridians is considered as the standard meridian and the time of this meridian is considered as the standard meredian and the time of this meridian is considered as standard Time of the country to eleminate the problems of time. This is called standard time.

Question 4.
What is the difference between the two places one of them lies to the earth of Greenwich and other lies to the West of Greenwich.
Answer:
The time of the place that lies to the east of Greenwich is more tham that of Greenwich. With the increasing of every meridian the time increases 4 minutes. The time of the place that lies to the west of Greenwich is less than that of Greenwich. With the increasing of every 1° meridian towards the west. the time decreases 4 minutes.

Question 5.
Why are the lines of latitudes and longitudes are important?
Answer:
The lines of latitude and longitudes are important to determine the location of a place on the Earth. The lines of latidudes and longitude determine the climate of a place. The temperture of lower latitude high moderate in middle and east at higher latitude. The climate is cold here. The meredian help to determine the time.

Question 6.
Distinguish between lines of latitudes and longitudes.
Answer:
The differences between the lines of tatidudesandl ongitudes are :

Lines of Latitudes	Lines of Longitudes
1. The line with same latitude is called the lines of latitude.	1. The line with same longitude is called the lines of longitude.
2. They are full circle.	2. They are half circle.
3. They are stretch from east to west.	3. They are stretch from North to South.
4. The length of the lines are not same.	4. The length of the lines are same.
5. The heighest value is $90^{\circ}$	5. The heighest value is 180°
6. There is no difference in temperature of two places lies in same latitude.	6. There is difference in climate of two places lies in same longitude.
7. They are parallel to each other.	7. They are not parallel to each other.
8. There is no changing in time with the change of latitude.	8. There is changing in time with the changed of longitude.

Question 7.
What is International date line? What is its importance?
Answer:
The 180° meridian which lies just opposite side of prime Meridian is known as international date line because from this line a new date starts or ends.
Importance : If two persons starts from Greenwich one of them towards east and other towards were when they reach at 180° meridian the time of the person. Who is from east will be irresed for 12 hours. But the time of the person who is from west will be decreased for 12 hours. To eleminate the problem 180° meredian is eonsidered as international date line. The person who crosses 180° and goes towards last the line will be decreases for one day and who goes to the east the time will be decreases for one day. so 180° menidian is called the lnternational dalite.

Question 8.
What is the importance of lines of latitude and longitude?
Answer:
Importance of lines of latitude-

• The lines of latitude have devided the Earth in diffeent climatie Zone.
• It can be understocd that how far a place is to the north or to the south of Equator.
• They devide the Earth into different temperate zones.

Importance of the line of longitude :

• The lines of longitude help to know the time.
• It can be known that how far a place is to the east of to the west of prime meridian.
• The pilot of the aircraft or the ship remain conscious about the lines of longitude.

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 1 Earth’s Revolution offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 1 Question Answer – Earth’s Revolution

Can you say?

Question 1.
How many rotations are completed in the course of one revolution?
Answer:
The Earth rotates 365 times to revolve once around the Sun.

Question 2.
How many minutes are there in 24 hours or 1 day?
Answer:
There are 1440 minutes in 24 hours or 1 day.

That’s easy
Now write down correctly.

year – leap year
2004 – yes
2000 – yes
2012 – yes
1900 – no
2013 – no
2100 – no

Have you thought (page no.-9)

When do you think we get more heat during day time?

All the time of sunrise
At noon when the sun is overhead
During sunset
At night after sunset
Answer:
At noon when the sun is overhead

Let’s get down to work (page no.-11)

Month – Direction from which the sun rises
March – middle of Eastern sky
May-June – kloser to North
September – middle of Eastern sky
November – closer to South.

The shadow in a Sundial : (Page no. 13)

Question 1.
On which day the length of the shadow is smallest?
Answer:
The length of the shadow is smalest on 21 st June.

Question 2.
On which day the length of shadow is longest.
Answer:
The length of shadow is longest on 22nd December at 12 O’clock noon.

Brainware (Page no. 16)

Think and solve :

What will happen if the axis of the Earth is perpendicular to the Earth’s orbital plane?
Answer:
The days and nights would be equal and there would be no season change.

If the axis of the Earth is in the same plane with its orbit?
Answer:
The days and nights would be equal and there would be no season change.

Where days and nights are equal?
Answer:
Days and nights are equal in the equatorial region.

What is the local time of sunrise in Tokyo, Kolkata and Sidney on 21st March?
Answer:
On 21 st March the sun rises at 5 p.m. in Tokyo Kolkata and Sidney.

What is local time of sunrise on 4th July, 25th January and 20th September at any place on the equator?
Answer:
On 4th July, 25th January and 20th September the Sun rises at the same time at any place of equator.

At what local time does the sun set in New York, Delhi and Cairo on 23rd September?
Answer:
The sun set in New York, Delhi and Cairo at 5 pm. on 23rd December.

Reverse Seasons in North and Southern Hemisphere (Page no. 17)
Answer:
21 st June-(i) hibiscous, mango, black berry, jackfruit,
(ii) the shortest night.
(iii) Starting of Winter.
23rd September- (i) The day and the night are equal.
(ii) equal day-night.
22nd December-
(i) The smallest night.
(ii) Marrygold, Dahlia, Apple, Orange
(iii) Starting of Summer.

CrossWord :

Across
1. The eighth planet
5. The shape of the earth’s orbit
6. The dramatic play of light in the night sky near the poles.
7. 23 1/2° N = Tropic of ………..

Up-Down
2. The position when the earth is farthest away from the Sun on its orbit.
3. Equal days and equal nights.
4. Our galaxy.

Do it yourself

In which season do we have a clear sky on most of the days?
Answer:
We have a clear sky in winte.

Name the season in which the earth is parched?
Answer:
The earth is parched in Summer.

Name the season in which ponds are full of water.
Answer:
Ponds are full of water in Rainy season.

Name the season in which floods are likely.
Answer:
Floods are possible in Rainy season.

Name the season in which you can actually fish in shallows and canals.
Answer:
Fishes are collected from shallows and canals in winter and spring.

In which season does the location of sunrise shift the most southward in the sky.
Answer:
The sun rises from extreme southward of the sky in winter.

In which season is the shadaw at 12 noon found to be the longest compared to the rest of the year?
Answer:
The shadow becomes longest at 12 noon in winter.

What is name of the season when you hear the cuckoo calling?
Answer:
Cuckoo calls in spring.

In which season is the day longest in the Northern hemisphere?
Answer:
Day is longer in northern hemisphere in summer.

Does the southern hemisphere feel warm or cold on 25th December?
Answer:
On 25th December southern hemisphere experiences hot.

Why the scientists visit Antarctica in December.
Answer:
Antarctica lies in south hemisphere. The south hemisphere experiences summer in December. For Dakshinayan the sunrays fall perpendicularly on Southern hemisphare at that time and thus the days are longer and nights are shorter. Then the summer begins. The ice starts melting in Antarctica. The weather becomes little pleasant. So the scientists visit Antarctica in December.

When do we come closer to the Sun July or January?
Answer:
We come closer to the sun in January.

Class 7 Geography Chapter 1 Question Answer West Bengal Board – Earth’s Revolution

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
At the time of creation the earth was thrown away from –
i) a unknown star
ii) universe
iii) the sun
iv) the moon
Answer:
iii) the sun

Question 2.
The sun is revolving around the centre of our galaxy-
i) alone
ii) with all its planets
iii) with all its planets and their satellites
iv) with earth
Answer:
iii) with all its planets and their satellites

Question 3.
The speed of earth’s annual motion or revolution is 30km per –
i) second
ii) minute
iii) hour
iv) day
Answer:
i) second

Question 4.
On 4th July the distance between the Sun and the Earth is-
i) mimimum
ii) maximum
iii) medium
Answer:
ii) maximum.

Question 5.
The time taken by the earth to move round the sun-
i) 365 days
ii) 366 days
iii) 366 days 5 hours
iv) 365 days 5 hrs 48m 46 sec
Answer:
iv) 365 days 5 hrs 48 m 46 sec

Question 6.
Oblique rays of the Sun cover a –
i) larger area
ii) smaller area
iii) i true, ii false
iv) i false, ii true
Answer:
iii) i true, ii false

Question 7.
When the Northern hemisphere is inclined towards the sun-
i) the days are longer
ii) temperature increases
iii) nights are shorter
iv) All are true
Answer:
iv) All are true

Question 8.
When the Southern hemisphere is inclined towards the sun-
i) summer prevails
ii) winter prevails
iii) spring prevails
iv) autumn prevails
Answer:
i) summer prevails

Question 9.
Sunrays fall vertically on the equator-
i) six months
ii) throughout the year
iii) three months
iv) nine months
Answer:
ii) throughout the year

Question 10.
In the period between 21 st June and 22 n December the sun apparently shifts
i) northward
ii) southward
iii) i true ii false
iv) i false ii true
Answer:
iv) i false ii true

Question 11.
On 21 st June Sun’s rays fall directly on-
i) Tropic of Capricorn
ii) Antarctic circle
iii) Tropic of Cancer
iv) none of these
Answer:
iii) Tropic of Cancer

Question 12.
In Northern Norway the Sun is clearly seen in the sky even at midnight from-
i) May to July
ii) January to March
iii) March to May
iv) July to September
Answer:
i) May to July

Question 13.
The Northern and Southern polar regions experience continuous days and nights for-
i) three months
ii) six months
iii) nine months
iv) one month
Answer:
ii) six months

Question 14.
In North Polar region the sun never sets below the horizon from-
i) 21st March to 21st June
ii) 21st January to 21st April
iii) 21st April to 21st July
iv) 21st March to 21st June
Answer:
iv) 21 st March to 21 st June

State whether True or False : (1 mark for each question)

1. Any object on the Earth is attracted to its centre.
Answer:
True

2. The Sun is 10 lakh times bigger than the earth.
Answer:
False

3. The moon revolves around the Earth.
Answer:
True

4. The Earth revolces around its own axis.
Answer:
True

5. The speed of annual motion or revolution of Earth is 10 km per second.
Answer:
False

6. Kepler introduced four laws.
Answer:
False

7. Artisicial satellites are launched into their orbits at escape velocity.
Answer:
True

8. On 4th July the distance between the Sun and the Earth is least.
Answer:
False

9. A year is calculated on the basis of one complete”revolution of the earth.
Answer:
True

10. North and south two polar region experience day and night with a span of six months.
Answer:
True.

11. On two polar belts the sun rays fall perpendicularly through out the year.
Answer:
False.

12. 22nd June the Sun rays fall directly on equator.
Answer:
False.

13. The Earth revolves round the Sun in an elliptical orbit.
Answer:
True.

14. From January to July the Earth goes far away the Sun.
Answer:
True.

Fill in the blanks : (1 mark for each question)

1. The attraction force of the Earths is called ______.
Answer:
Gravitational force.

2. The Earth is ______ times smaller than the Sun.
Answer:
13 Lakhs.

3. The rate of revolution of the Earth is ______ per second.
Answer:
30 km.

4. Earth’s Aphelion occurs on _____.
Answer:
4th July.

5. Earth’s perihalion occurs on ______.
Answer:
3rd January.

6. The year consisting 366 days is called ______.
Answer:
Leap year.

7. On 21st June the Sun rays fall perpendiculary on ______ and 22 and December. The Sun rays fall perpendicularly on ______.
Answer:
Tropic of cancer, Tropic of capricon.

8. The Sun’s apparent migration is called ______.
Answer :
Rabi Marg.

9. The Earth is ______ inclined on its orbit.
Answer:
66 1/2°,

10. The upper end of the Earth is called ______ and lower end is called ______.
Answer:
North pole, South pole.

11. The Escape velocity is ______ per second.
Answer:
11.2 km per second.

12. The-mon revolves round the Earth in ______ days:
Answer:
28 .

13. The period between 22nd December to 21 st June the Sun apparent motion towerds the north is called ______.
Answer:
Northern Solstice.

14. The span of this day longest in Northern hemisphere on ______.
Answer:
21 st June.

15. ______ Land is known as the Jand of Midnight Sun.
Answer:
Hammerfest port.

Match the column A with columo B.

Column A	Column B
a) On 21st March Sun’s rays fall	i) is not seen in the Arctic region
b) On 21st June Sun’s rays fall	ii) gets egual day and night
c) Equinox means	iii) is 21 st June
d) From September to January the Sun	iv) in 365 days
e) In Northern Hemisphere 2 sst March	v) directly on the equator
f) Longest day in Southern Hemisphere	vi) as a leap year
g) Shortest day in Southern Hemisphere	vii) directly on the Tropic of Cancer
h) The Earth revolves round the sun	viii) on 4th July is maximum
i) $\mathbf{2 0 1 2}$ is considersd	ix) equal day and night
j) The distance between Sun and the Earth	x) 22 nd December

Answer:
a) On 2 kst March Sun’s rays fall directly on the equator.
b) On 2 lst June Sun’s rays fall directly on the Tropic of Cancer.
c) Equinox means equal day and night.
d) From September to January the Sun is not seen in the Arctic region.
e) In Northern Hemisphere 21 st March gets egual day and night.
f) Longest day in Southern Hemisphere 22nd December.
g) Shortest day in Southern Hemisphere is 21 st June.
h) The Earth revolves round the sun in 365 days.
i) 2012 is considersd as a leap year.
j) The distance between Sun and the Earth on 4th July is maximum.

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What is the name of the milky way the Earth belongs to?
Answer:
The Earth belongs to the milky way named Akash Ganga.

Question 2.
What is the axis of the Earth.
Answer:
The imaginery line around which the Earth rotates is called the axis of the Earth.

Question 3.
What is ‘Escape velocity’?
Answer:
At which speed moving object can avoid the gravitational force of the Earth is called Eacape velocity.

Question 4.
What is the shape of the Earth?
Answer:
The shape of the Earth is spherical.

Question 5.
What is Luner month?
Answer:
The moon the satellite of Earth takes 28 days to revolve the Earth. This is called ‘luner month’.

Question 6.
What is equinox?
Answer:
The equinox means the equal length of day and night.

Question 7.
On which day the day and night is equal through out the world?
Answer:
On 21 st March and 23rd September the day and night are equal throught out the world?

Question 8.
Which day is called vernal equinox?
Answer:
2 ist March is called vernal equinox.

Question 9.
Which day is known as Autumnal equinox?
Answer:
23rd September is known as Autumnal equinox?

Question 10.
What is called the land of Midnight Sun?
Answer:
Hammerfest port in Northern Norway is called the land of Midnight Sun.

Question 11.
Who stated first about the actual motion of the planet?
Answer:
Scientist Kepler stated first about the actual motion of the planet.

Question 12.
What is the shape of the orbit of the Earth?
Answer:
The orbit of the Earth is elliptical.

Question 13.
How many season are there in a year?
Answer:
There are six seasons in a year.

Question 14.
from where we can sea the Aurora Borialis and Aurora Austratis?
Answer:
We can see a Aurora Borialis from Narth pole and Aurora Australis from south pole.

Question 15.
Name two seasonal flowers of Autumn?
Answer:
Two seasonal flowers of Autumn are Seuli and cas.

Question 16.
Why is the distance between the Sun and the Eakth is not always same?
Answer:
The distances between the Sun and the Earth is not always same as the Sun stays at one focus of the eliptical orbit.

Question 17.
Or which days the distance between the sun and the Earth is lowest?
Answer:
The distance between the Sun and the Earth is lowest on 3rd January.

Question 18.
What is solar year?
Answer:
The Earth takes 365 days to revolve rotnd the Sum. This is called Solar year.

Question 19.
On which days the Sun rays falls perpendicuharly on the Equator?
Answer:
On 21st June and 22nd December the Sun rays fall perpendicularly on the Equator?

Question 20.
On which day Summer solstice occurs?
Answer:
Summer solstice occurs on 21 st June.

Question 21.
On which day Winter Solstice occurs?
Answer:
Winter Solstice occurs on 22nd December.

Question 22.
What is the value of Arctic Circle?
Answer:
The value of Arctic Circle is 66 1/2° North.

Question 23.
Which day is called vernal equinox?
Answer:
21 st March is called vernal equinox.

Question 24.
Which day is called Autumnal eqinox?
Answer:
23 td September is called Autumnal eqinox.

Question 25.
What is called the apparent soutly ward nigration of the Sun.
Answer:
The apparent south ward migration of the S(u) is called Dakshinayan.

Question 26.
What is the value of the Tropic of capricon.
Answer:
The value of the Tropic of capricon is 23 1/2° South.

Question 27.
Which is the longest day and shortest night in the northern hemisphere?
Answer:
21 st June is the longest day and shortest night in the northern hemisphere.

Question 28.
How much is the East inclined on its orbit?
Answer:
66 1/2°

Question 29.
In which hemisphere our country is situated?
Answer:
Our country is situated in Northern hemisphere.

Question 30.
What is the rate of revolution of Earth per second?
Answer:
the rate of revolution of Earth per second is 30 km.

Question 31.
Who thought first about leap year?
Answer:
Egyptians thought. first about leap year.

Question 32.
What is the source of life on Earth?
Answer:
The Sun is the source of life on Earth.

Question 33.
Which season does the Southern hemisphere enjoy where there is Autumn in Northern hemisphere?
Answer:
Spring.

Short Questions & Answers : (2 marks for each question)

Question 1.
What is rotation?
Answer:
The Earth rotates around its own axis like a top from west to east. It takes 24 hours for one rotation. This is called the rotation of the Earth. Day and night cause due to the rotation of the Earth.

Question 2.
How many motions does the Earth have? What are they?
Answer:
The Earth has two types, of motion. They are rotation and revolution.

Question 3.
What is revolution of Earth? Give the result of its :
Answer:
The Earth revolved around the Sun on its elliptical orbit spinning around its owm exis a like a top. This is called revolution.
Revolution causes the season change and increasing and decreasing of the length of the day.

Question 4.
What is Aphelion and Perihelion?
Answer:
Aphelion is the point of the Eart’s orbit that is farthest away from the Sun. The Perihelion is the point of the Earth’s orbit that is nearest to the Sun.

Question 5.
What is Autummal eqinox?
Answer:
On 23rd September the Sun rays fall directly on Equator. For this reason the d.ys and night equal through out the Earth. The northern hemisphere experences autumn. Thus it is called: Autumnalequinox.

Question 6.
What is summer solstice.
Answer:
On 21 st June the Sunrays fall directly of tropic of cancer: On thit day the is longest in Northern hemisphere and smallest.in Southern hènisphere. Arctic circle experience day light fir 24 hours. Antertic circle remain in darkness for 24 hours. It is called Summer solstice:

Question 7.
What is Rabi Marg of the apparent annual motion of Sun?
Answer:
The Earth is 66 1/2° inclined on its plane of orbits, So the Sun ray falls sometines perpendicularly, sometimes inclined or Equator. Tropic of cancer and Trcpic of capricon. So the – Sun seems to migrate from Equator to Tropic of cancer to the month and them to Tropic of Capricon to the Sotth: This is called the Rabi Marg and the apperent annual motion of Sun.

Question 8.
What is Uttarayan and Dakshinyam.
Answer:
On 22ud.Décember the Sunrays fall directly on Tropic of capricon and then it gradually becomes inclined towards the north pole. Thus it seems that Sun-migrates towards northand this is called Uttarayan. From 21st June to 22 nd Đecember the apparent migration of the Sun towards Soutli is called. Dakshinayan.

Question 9.
What is Aurora Borialis and Aurora Australis?
Answer:
In the north polar-region -and in the south polar region, when there are day and night -with a spati of six months a tight like a rainbow seen or the sky: It is the result of the colfision of sun – ray and the ionised gas present in atmosphere. In north pole it is called Aurora Borialis and in south pole it is called Aurora Australis.

Question 10.
What do you know about Aphelion and Perihelion.
Answer:
The Sun ties at the focus point of the ellipticat orbit of the Earth. So the distance between the Earth and the Sun is not the same at the time of revolution. On 4th July the distance between the Sun, and the Earth is maximum almost 15 crore 20 Lah km. This is called Aphelion On the other hand the distajce between the Sun and the Earth is towest on 3rd January almost 14 crorer 70 lakh km. This is called Perihelion. For this reason the Sun look bigger in winter and smaller in summer.

Long Questions & Answers : (3 marks for each question)

Question 1.
What is leap year?
or,
Why does the month of February not consist 29 days all time?
Answer:
The Earth takes 365 days 5 hours 48 minutes 46 second to complete one revolution but we take 365 days for a year to make the calculation easy. So the extra 5 hours 48 minutes and 46 second is considered as a day after 4 years and is added with the days of February every fourth years. So every fourth years the month of February consists 28+1=29 days the year cortsists 366 days. Thiş year is called leap year. The year. which is totally devisible by four and there is no remainder, is called leap year. But the century years (such as 1900.2000 , should be divided by 400 to calculate correctly.

Question 2.
Write the important factors at the time of revolving of the earth around the Sun.
Answer:
The important factors are-
(i) Spinning like a top on its own axis the Earth completes one revolution around the Sun in 365 days.
(ii) The Earth’s axis is always tilted.
(iii) The shape of the Earth’s orbit is elliptical.
(iv) The Earth’s axis is 66 1/2 inctined or its orbit and the plane of orbit is 23 1/2° inclined on the equarorialplane.
(v) The Sun ties at the focus of the Earth elliptical orbit and for this reason the distance between the Sun and the Earth is not always the same. The rate of the revolution changes due to this fact. For the changes of the distance the sun fooks sometimes biggers and sometimes smaller.
(iv) The Earth revolves the Sun from East to West.

Question 3.
What do you Undurstand by the turn ‘season change’? How do the advent of the different seasons occur in the two hemisphere?
Answer:
The temperature of the different places and differnt times verious for the different inclination of the Sun rays and the increase and decrease of this length of the day. Based on these difference the whole year in divided into some parts. Each of the part is considered as a season. The changing of the season in a circleing way is called season change. Four season dominate in the Earth. They are summer autumn, winter and spring.

a) The spring in Northern hemispher: At time of rotation of its own axis they cones such a point from where the sunrays fall vertically on the equator. Then the two pole of the Earth lie at the same distance from the sun. Thy day and night are equal at all the places of the Earth. The day is with the span of 12 hours and night is also of 12 hours. This is known as autumnal equinox. The weather is pleasant as the day and night are equal. At that period the northern hemisphere enjoyes spring and autumn prevails in Southern hemisphere.

b) Summer in Northern hemisphere: After 21 st March the Northern hemisphere gradually comes towards the sun. The sun reaches the end point of Uttarayan. On that day the sun rays fall vertically on the equator. So the northern hemisphere experiences the day more than 12 hours and the night less than 12 hours. For the longer days and the vertical sunrays one and half months before and after 21 st June the weather is better in northern hemisphere and the opposition condition is found in southern hemisphere. 21 st June is called the Summer Solstice.

c) Autumn is Northern hemisphere : After 21 st June the southern hemispherc comes closer to the Sun the Dakshinayan of the Sun starts. On 23rd September the two poles remain at the same distance from the sun. On that day the sun rays fail on the equator. The days and nights are same through out the world. The weather remains pleasant. There is autuma in norther: hemispliere and spring in Southern hemisphere. Thus on 23rd september there is autumn in northern helmisphere and spring in southern hemisphere. 23 rd September is autumnal equinox in northern hemisphere.

d) Winter in Northern hemisphere : After 23 September the sunrays fall vertically on southern hemisphere. The sun rays fall vertically on Tropic of capricon on 22 nd December on that day the Southern hemisphere has the longest days and the smallest day. During one and half month before and after 23rd September the summer season prevails in soutiern hemisphere. This day is called salstice. In northern hemisphere has the shortest day and the longest night. So it is winter in Northern hemisphere.

Additional Questions and answers

Question 1.
Definc revolution of earth.
Answer:
Movement of the earth around the sun on a fixed path or orbit is called revolution.

Question 2.
Write the charaçteristics of revolution:
Answer:

1. Annual motion of the earth around the sun is called revolution.
2. The time of revolution is 365 days 6 -bours.
3. The change of season takes placedue to the revolutiom of the earth.

Question 3.
What is orbit?
Answer:
Orbit. is the eclliptical path on which heavenly bodies move around the sun or planet.

Question 4.
What is – axis?
Answer:
The axis of the earth is an inganinary line joining the north pole with the south pole.

Question 5.
Why do seasons change on the earth?
Answer:
Due to change in the position of the earth around the sun.

Question 6.
What is leap year?
Answer:
Six honrs saved eyery year in revolution are added in four years. They become 24 hours or one additional day. The day is added to the month of February every four years. So every fourth year February has one more day-29 days instead of 28 days. Such a year of 366 days – is called a leap year.

Question 7.
Mehtion the natural ways by which we can measure time.
Answer:
First method- Day and night occurs within 24 hours. When the Earth rotates, – sometimes it takes us away from the Sun. But again it makes us face the Sun. In fact, the Earth rotates slowly under the Sunrays. The portion of Earth.which receives the Sun’s rays experiences day while the other half of ths Eart has night.

Second method- The Earth’s satellite, Moon, revolves around the Earth in about 27 1/2 days. This is called a Lunar month”: Although 30 days is the standard duration of the month, some months have 31 or even 28 days.

Third methot-Revolution of the Earth. The Earth revolves around the Sun in 365 days. This time is called solar year. A year is calculated on the basis of one complete revolution of the earth. So revolution is also called the Annual Motion.

Question 8.
Why do seasons occur?
Answer:
When the Northern hemisphere is inclined towards the Sun, the days become gradually longer and nights gradually shorter there. The duration of daytime thus increases. The Earth gets lieated througliout the day.As nights are shorter, the Earth does not get enough time to cool down. So femperature keeps rising. During this period the Northern hemisphere gets direct Sunrays. So temperature increases. This is summer time in Northern Hemisphere but winter time in Southern Hemisphere.

When the Southern Hemisphere’ is inclined towards the Sun, the days shorteri and nights lengthen inthe Northern Hemispliere. The Sumlight does not.persist for a longtime, so the Earth does not get heated intensely. It cools down through out the long nights. During this period the Northern Hemir spinere receives oblique Sunrays, So it gets less heated. In this period winter prevails in Northern Hémisphere but summer prevails in Southern Hemisphere.

Question 9.
What is illuminated night and dark day?
Answer:
Beyond Arctic’ and. Antarctic circles the ‘Sunrays fall obliquely through the year. – From 2.1st March to 21 st June in North Polar region the Sun never sets below the horizon: In this period this-region receives Sunlight throughout 24 hours. That means the Sun shines even at night-as per their local time. From 23rd September to 22 ind December the same thing happens in the Southern Hemisphere.

From March to June or July, many parts of Canada, Alaska, Norway, Sweden and Icéland receive sunlight even at midnight. From Hammerfest port situated in Northern Norway the Sun is clearly seen (May to July) in the sky even at midnight. So this land is called Land of the Midnight Sun.

From September to January the Sun is never seen in the Arctic region. Darkness prevarls for 24 hours. This means that the Sun is not seen in the sky ever if it is day time as per local timings. From March to June the same thing happens in the Antarctic region.

WBBSE Class 7 History Question Answer West Bengal Board

WBBSE Class 7 History Book Solutions West Bengal Board in English Medium

• Chapter 1 The Idea of History
• Chapter 2 Some Aspects of Indian Political History: A.D. 7th Century to 12th Century
• Chapter 3 Some Aspects of Indian Society, Economy and Culture: A.D. 7th Century to 12th Century
• Chapter 4 The Delhi Sultanate: Turko-Afgan Rule
• Chapter 5 The Mughal Empire
• Chapter 6 Towns, Traders and Trade
• Chapter 7 Lifestyle and Culture: Sultanate & Mughal Era
• Chapter 8 The Crisis of the Mughal Empire
• Chapter 9 India Today: Government, Democracy and Self Governance

WBBSE Class 7 History Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 इतिहास की अवधारणा
• Chapter 2 भारतीय राजनैतिक इतिहास की विभिन्न धाराएँ (700-1200)
• Chapter 3 भारतीय समाज, अर्थनीति एवं संस्कृति की विभिन्न धाराएँ (700-1200 ई०)
• Chapter 4 दिल्ली सल्तनत तुर्की अफगान शासन
• Chapter 5 मुगल साम्राज्य
• Chapter 6 नगर, व्यापारी और व्यवसाय
• Chapter 7 जीवन यात्रा और संस्कृति सल्तनत और मुगल काल
• Chapter 8 मुगल साम्राज्य का संकट
• Chapter 9 सरकार, गणतंत्र और स्वायत्त शासन

WBBSE Class 7 Solutions

WBBSE Class 7 Geography Question Answer West Bengal Board

WBBSE Class 7 Geography Book Solutions West Bengal Board in English Medium

• Chapter 1 Earth’s Revolution
• Chapter 2 Determination of the Location of a Place on the Earth’s Surface
• Chapter 3 Air Pressure
• Chapter 4 Landforms
• Chapter 5 River
• Chapter 6 Rock and Soil
• Chapter 7 Water Pollution
• Chapter 8 Soil Pollution
• Chapter 9 Continent of Asia
• Chapter 10 Continent of Africa
• Chapter 11 Continent of Europe

WBBSE Class 7 Geography Book Solutions West Bengal Board in Hindi Medium

• Chapter 1 पृथ्वी की गति
• Chapter 2 धरातल पर किसी स्थान की स्थिति का निर्धारण
• Chapter 3 वायु दबाव
• Chapter 4 भू-आकृति
• Chapter 5 नदी
• Chapter 6 चट्टान और मिट्टी
• Chapter 7 जल प्रदूषण
• Chapter 8 मिट्टी प्रदूषण
• Chapter 9 एशिया महादेश
• Chapter 10 अफ्रीका महादेश
• Chapter 11 यूरोप महादेश

WBBSE Class 7 Solutions