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.
- Erosion : The river struck the side rocks by the water current in upper course.
- Transportation : The eroded rock particles are transported by the river water.
- 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.
- 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.
- 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.
- 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.
- 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.