Samacheer Kalvi 7th Social Science Term 1 Geography Solutions Chapter 2 Pdf
Tamilnadu Board Samacheer Kalvi 7th Social Science Term 1 Geography Solutions Chapter 2: Tamilnadu State Board Solution Class 7 Social Science Term 1 Geography Chapter 2 – Landforms.
Samacheer Kalvi 7th Social Science Geography Solutions Chapter 2: Overview
Board |
Samacheer Kalvi |
Class |
7 |
Subject |
Social Science Geography |
Term |
1 |
Chapter Name |
Landforms |
Unit 2 : Landforms
Multiple choice questions: (marks:1)
1.) The place of origin of the river is known as its:
A.) Source
B.) River mouth
C) Meanders
Ans: source.
2.) The place where river joins a lake or sea or an ocean is known as:
A.) Source
B.) River mouth
C.) Meanders
Ans: River mouth.
3.) A stream or river that flows into and joins a main river is called:
A.) Distributary
B.) Tributary
C.) Waterfall
Ans: Tributary.
4.) A stream that branches off and flows away from a mainstream is known as:
A.) Distributary
B.) Tributary
C.) Alluvial fan
Ans: distributary.
5.) An isolated residual hill standing like a pillar with rounded top are called:
A.) Inselbergs
B.) Mushroom rocks
C.) Sand dunes
Ans: inselbergs.
Answer the following questions: (marks:1)
1.) What is called a river?
Ans: The water flowing from its source to river mouth,along a definite course is called a river.
2.) What is known as a ‘v’ shaped valley?
Ans: The running water in the river erodes the mountainous track, which creates a steepsided valley like the letter ‘V’ known as ‘V’ shaped valley.
3.) What is known as a waterfall?
Ans: Falling of river water over a vertical step in the river bed is called a waterfall.
4.) What is a plunge pool?
Ans: plunge pool is a hollow feature at the base of a waterfall which is formed by cavitation.
5.) What do you mean by alluvial fan?
Ans: Alluvial fan is a deposition of sediment at which the river enters a plain or the foothills.
6.) Which is the highest waterfall in the world?
Ans: Angel falls of venezuela in South America is the highest waterfall in the world.
7.) Which waterfall is located between the borders of Canada and the USA in North America?
Ans: Niagara falls is located between the borders of Canada and USA in North America.
8.) In between the borders of Zambia and Zimbabwe which waterfall is located?
Ans: Victoria falls is located between the borders of Zambia and Zimbabwe.
9.) What are called sediments?
Ans: when the river floods, it deposits layers of fine soil and other material called sediments.
10.) The raised banks are called………..
Ans: levees.
11.) The crescent shaped sand dunes are called…………
Ans: barchans.
12.) What is called loess?
Ans: When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called Loess.
Answer the following questions: (marks:2/3)
1.) What are the two processes of resulting landforms?
Ans: The earth has an infinite variety of landforms named mountains, plateaus, plains, valleys etc. Some parts of the lithosphere may be rugged and some flat. These landforms are a result of two processes. They are i. The Endogenic Process ii. The Exogenic Process
(i) The Endogenic Process:
The endogenic process or internal process leads to the upliftment and sinking of the earth’s surface at several places.
(ii) The Exogenic Process:
The exogenic process or external process is the continuous wearing down and rebuilding of the land surface.
2.) What is weathering and erosion?
Ans: The landscape is being continuously worn down by two processes: weathering and erosion.
Weathering: is the breaking and falling apart into small pieces of the rocks on the earth’s surface.
Erosion:is the wearing down of the landscape by different agents like water, wind, ice and sea waves. The eroded material is carried away by water, wind, etc. and eventually deposited. This process of erosion and deposition creates different landforms on the surface of the earth.
3.) What do you know about meanders?
Ans: The term ‘Meander’ has been named on the basis of Meander River of Asia Minor in Turkey, which flows through numerous curves and turns.As the river enters the plain it twists and turns forming large bends known as Meanders.
4.) What is cirque and arete?
Ans: Cirque is a glacially decayed rock basin, with a steep side wall and steep head wall, surrounding an armchair-shaped depression. E.g. Corrie in Scotland, Kar in Germany. When two adjacent cirques erode towards each other, the previously rounded landscape is transformed into narrow rocky, steep sided ridges called Arete.
5.) What are called Tarn lakes?
Ans: When the ice melts ,they fill up the cirque with water. Cirque is a glacially decayed rock basin, with a steep side wall and steep head wall, surrounding an armchair-shaped depression.when the ice melted water fills up with water and becomes beautiful lakes in the mountains called Tarn lakes.
6.) What are the famous lagoons of India?
Ans: Chilika lake in Odisha, rulicat lake in Tamil Nadu and vembanad lake in kerala are tye famous lagoons of India.
7.) Which are the longest and second longest beaches in the world?
Ans: The longest beach in the world is Miami beach in South Florida in the USA and the second longest beach in the world is the Marina beach in Chennai.
Answer the following questions: (marks:5)
1.) What are the landforms produced by sea waves?
Ans: The earth has an infinite variety of landforms named mountains, plateaus, plains, valleys etc. The coastal areas are subject to change due to wave erosion and wave deposition. The erosion and deposition of the sea waves give rise to coastal landforms. The landforms produced by sea waves are as follows:
- Sea coast: A part of the land adjoining or near the sea is called the Sea coast.
- Coast line: The boundary of a coast where land meets water is called the Coast line.
- Sea Cliffs: sea cliffs are steep rock faces formed, when the sea waves dash against them.
- Sea caves: Sea waves continuously strike at the rocks. So Cracks develop. Over time they become larger and wider. Thus, hollow like caves are formed on the rocks. They are called Sea Caves.
- Sea arches: when the cavities of sea caves become bigger and bigger only the roof of the caves remains, thus forming Sea Arches.
- Sea stacks: When the erosion of the caves breaks the roof and only walls are left. These wall-like features are called Sea Stacks.
- Beaches: The sea waves deposit sediments of sand and gravel along the shores forming Beaches.
- Sand bar: Sand bar is an elongated deposition of sand or mud found in the sea, almost parallel to the coast.
- Lagoon: lagoon is a shallow stretch of water partially or completely separated from the sea. E.g. Chilika lake in Odisha, Pulicat lake in Tamil Nadu and Vembanad lake in Kerala are the famous lagoons in India.
2.) What are the landforms produced by the wind?
Ans: An active agent of erosion and deposition in the deserts is wind. The landforms produced by the effects of wind are:
- Mushroom rocks: Winds decrease the lower section of the rock more than the upper part. Therefore, such rocks have narrower bases and wider tops. Wider top rocks in the shape of a mushroom, commonly called mushroom rocks.
- Inselbergs: An isolated residual hill, standing like a pillar with rounded tops are called Inselbergs. E.g. Inselberg in the Kalahari desert of South Africa.
- Sand dunes: When the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hill-like structures. These are called sand dunes.
- Barchans: The crescent shaped sand dunes are called Barchans.
- Loess: When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called Loess. Large deposits of loess are found in China.
3.) Write down about the landforms produced by a river?
Ans: The water flowing from its source to the river mouth, along a definite course, is called a River. The landforms produced by a river are: Rivers generally originate from a mountain or hill.
- V shaped valley: The running water in the river erodes the mountainous track, which creates a steep-sided valley like the letter ‘V’ known as ‘V’ shaped valley.
- Plunge pool: plunge pool is a hollow feature at the base of a waterfall which is formed by cavitation.
- Alluvial fan: Alluvial fan is a deposition of sediment at which the river enters a plain or the foot-hills.
- Meanders: As the river enters the plain it twists and turns forming large bends known as Meanders. Eg. Meanders along the River Vellar near Sethiyathope in Cuddalore District, Tamil Nadu.
- Ox bow lake: Due to the continuous erosion and deposition along the sides of the meander, the ends of the meander loops come closer. In due course of time the meander loop cuts off from the river and forms a cut-off lake, also called an Ox-bow lake.
- Sediments: At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As the river floods, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain. The raised banks are called levees.
- Delta: The velocity of the river becomes so slow that it begins to deposit its load. The collection of sediments from all the mouths form Delta. Deltas are excellent productive lands. For example, Cauvery delta, Ganges delta, Mississippi delta.
- Glacier: A large body of ice moving slowly down a slope or valley due to gravity is called a glacier. The types of the glacier are: continental glacier and mountain or valley glacier.
- Cirque is a glacially eroded rock basin, with a steep side wall and steep head wall, surrounding an armchair-shaped depression. Such as, Corrie in Scotland, Kar in Germany.
- Tarn lakes: As the ice melts, they fill up the cirque with water and become beautiful lakes in the mountains called Tarn Lake.
- Arete: When two adjacent cirques erode towards each other, the previously rounded landscape is transformed into narrow rocky, steep sided ridges called Arete.
- U shaped valley: U Shaped Valley is found beneath the glaciers which is deepened and widened by the lateral and vertical erosion.
- Glacier moraines: The material carried by the glacier such as rocks – big and small, sand and silt get deposited. These deposits form glacial moraines.
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