Question 1

Question 3Name the different types of mountains. Describe each of them with examples.

Accepted Answer

The different types of mountains are as follows:Fold mountains — The fold mountains are formed by horizontal movements of the crust resulting in wrinkle like folds that vary greatly in size. The folds have arched or upraised parts known as anticlines and troughs known as synclines. Based on the period of their formation they are of two types — young fold mountains like the Himalayas and old fold mountains like the Aravalis.Block mountains — Sometimes movement of earth's crust causes cracks or faults, where such movement leaves a block of higher land standing between two areas of lower land, the highland is known as a 'Block Mountain' or Horst. For example — the Vosges and Black forest mountains, Satpura and Vindhya mountains in India.Residual mountains — When an area of highland remains standing above the general level after rivers and other natural agents have lowered the surface of the surrounding area, the term residual mountain is used. Sometimes such highlands are called mountains of denudation. For example — Helvellyn Residual Mountain

Question 2

Question 7Explain the types of depositional plains.

Accepted Answer

The types of depositional plain are:Alluvial plains — These are formed by gradual accumulation of silt brought down by rivers. These deposits may be fan shaped known as Piedmont alluvial fan. When the river widens its valley or overflows its banks during floods, the clay and sand deposit to make flood plains. Examples are Indo-Gangetic plains, Plains of northern China and Mississippi plain. At the mouth of a river, triangular shaped plain of deposited material is called delta plain.Glacial deposits — When the glaciers melt, the debris are deposited. Such plains are extensive in size and very fertile. They have irregular surface. For example, Plains of Central North America and Western European plain.Aeolion Loess Plains or deposition by winds — These plains are formed by the materials which have been transported or deposited by winds. For example, Loess deposits of North China.Lacustrine plains or river deposits — These plains result from the fillings of lake beds. When rivers enter a lake, they are muddy. The plains of Hungary in Europe and the plains of surrounding great lakes of North America are examples.

Question 3

Question 9Differentiate between intermontane plateau and volcanic plateaus.

Accepted Answer

S.No.Intermontane plateauVolcanic plateaus1.They are surrounded by hills and mountains on all the sides.They are formed by numerous volcanic eruptions.2.They are formed along with fold mountains.They are slowly formed over time.3.Example- Tibetan PlateauExample- Peninsular plateau of India.

Question 4

Question 10Define a plain. How does it differ from a plateau?

Accepted Answer

Plain is an extensive fertile tract of flat land, a gently and undulating terrain without prominent hills or depressions, usually formed by deposition of eroded material brought by rivers, glaciers and wind.S.No.PlainsPlateaus1.They are low lying area.They are relatively high areas.2.They are fertile.They are relatively less fertile.3.They have gradual slope.They have steep and abrupt slope.4.They have less mineral deposits.They are rich in mineral deposits.5.Example, Gangetic Plains of Northern IndiaExample, Deccan Plateau of India

Question 5

Question 12State any two characteristics of young fold mountains.

Accepted Answer

Two characteristics of young fold mountains are:Ruggedness of relief and rounded contours of mountain areas.Most of the active volcanoes are found in their neighbourhood.

Question 6

Question 14How are alluvial plains formed?

Accepted Answer

Alluvial plains are formed by gradual accumulation of silt brought down by rivers. As a river leaves the mountains, the water spreads out and fast speed is arrested. The sluggish water deposits the material brought by it forming the plains. They mostly deposit the eroded materials along the foot of hills forming Piedmont Alluvial plain, like Bhabhar in India. Plains are also formed by the flooded rivers and are known as flood plains.Examples of fertile alluvial plains are Indo-Gangetic plains, Mississippi plain, etc.

Question 7

Question 15Give an example each of the following :Fold mountainsBlock mountainVolcanic plateauStructural plain

Accepted Answer

Fold Mountain — The HimalayasBlock mountain — Fault Block Mountain (Pakistan)Volcanic plateau — The Columbian PlateauStructural plain — Russian platform

Question 8

Question 13Assertion (A): The forces of faulting lead to the formation of block mountains.Reason (R): Block mountains are often separated by intervening basins called graben.Both A and R are true and R is the correct explanation of A.Both A and R are true but R does not explain A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true but R does not explain A.Explanation — The forces of faulting, also known as epeirogenic forces, lead to the formation of Block mountains. Due to tensional force, cracks or faults may occur on the earth's crust. If two parallel faults occur, the land in between subsides to form a rift valley. If a block rises, it forms a horst or block mountain.

Question 9

Question 16Depositional plains formed as a result of action of wind have irregular and undulating surface because ofnew deposits made everyday.existence of sand dunes and hallows.existence of scrubs.All of the above.

Accepted Answer

existence of sand dunes and hallows.

Question 10

Question 17A piece of land reclaimed from the sea or lake:HorstGrabenDykePolder

Accepted Answer

Polder

Question 11

Question 18The plains that are formed due to uplift or subsidence of land are called:Structural plainsDepositional plainsPlainsLandforms

Accepted Answer

Structural plains

Question 12

Question 19Which of the following pairs is incorrectly matched?Structural Plains : Coromandel PlainsWind Deposition Plains : Thar DesertRiver Deposition Plains : Northern Plains (India)Marine Deposition Plains : Western Coastal Plains (India)

Accepted Answer

Marine Deposition Plains : Western Coastal Plains (India)

Question 13

Question 20Epeirogenic forces lead to the formation of Block Mountains. In this context which of the following are true?Horst — block mountains with flattened summits.Graben — basins separating block mountains.Vosges — example of block mountains.All of the above.

Accepted Answer

All of the above.

Question 14

Question 21Name the plateaus, formed along with fold mountains, that are surrounded by hills and mountains on all sides.Volcanic PlateausStructural PlateausIntermontane PlateausDepositional Plateaus

Accepted Answer

Intermontane Plateaus

Question 15

Question 22Assertion (A): Many lakes exist in the vast lowland of the Great Plains of the USA.Reason (R): The Great Plains were formed due to uplift of land submerged under water.Both A and R are true and R is the correct explanation of A.Both A and R are true but R does not explain A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.Explanation — The fact that they were submerged under water is responsible for the existence of many lakes in the vast lowland.

Question 16

Question 11Give two points of importance of landforms.

Accepted Answer

The importance of landforms are-The mountain ranges of the world are the abode of snow and glaciers. They are thus the source of perennial rivers.Mountains, plateaus, plains and valleys are beautiful sculptures of nature on the surface of the earth. They add to the beauty of the earth.

Question 17

Question 1(a)How are various landforms formed on the surface of the earth?

Accepted Answer

Landforms are formed on the surface of the earth due to the following natural processes-1. Plate Tectonics — The tectonic plates push, collide and slide past each other due to which sedimentary rocks are compressed. This causes folding of the rocks and forms fold mountains.2. Uplift and Submergence — A set of forces operates inside the earth's centre to the surface and is characterized by large scale uplift and subsidence of land area. These forces result in the formation of block mountains, basins, rift valleys, plateaus, plains, lakes and big faults.3. Exogenic Forces — These forces cause widespread destruction through weathering and erosion of existing landforms and form new landforms through both erosion and deposition.

Question 18

Question 1(b)Describe the formation of mountains and their types.

Accepted Answer

A mountain is a very steep land or hill rising to great heights above the land surrounding it. Mountains are classified into three types based on the forces that have formed them.1. Fold mountains — Fold mountains are the result of large-scale earth movements caused by stresses in the earth’s crust. Such stresses may be caused by weight of the overlying rocks, movements in the mantle, the expansion or contraction of some part of the earth, etc. These stresses subject the rocks to compressive forces, producing wrinkling or folding along the lines of weakness. For example- the Himalayas in India.2. Residual Mountains — Mountains which are subjected to weathering and erosion for a longtime, are lowered down and called residual or relict mountains. Denudation and erosion by natural agents like winds, water, snow etc., cause the mountains to be lowered but some resistant areas may remain and form residual mountains. They may also be formed on plateaus that are dissected by rivers. For example- Nilgiri in India.3. Block Mountains — It is an uplifted land mass situated between two adjacent faults. The central block is upthrown or land on the outer-sides of the faults is downthrown so that the central mass appears like a highland. Its surface is like a plateau, but it has steep edges. For example- Vosges in Europe.

Question 19

Question 1(d)Draw a well labelled diagram to show the formation of block mountain.

Accepted Answer

Please refer to the full solution above.

Question 20

Question 2(a)Describe the characteristics of two different types of plateaus.

Accepted Answer

The characteristics of Intermontane plateau are-These plateaus are surrounded by hills and mountains on all sides.They are formed along with fold mountains.For example- the Tibetan plateau.The characteristics of Volcanic plateaus are-They are formed by numerous volcanic eruptions that slowly build up over time, forming a plateau.For example- the Peninsular Plateau of India.

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