1st PUC Geography Question Bank Chapter 4 Landforms

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Karnataka 1st PUC Geography Question Bank Chapter 4 Landforms

1st PUC Geography Landforms Text Book Questions and Answers

I. Answer the following in a word or a sentence each.

Question 1.
What is the geomorphic process?
Answer:
The processes carried out by the Endogenic agents i.e., the agents which bring change inside the earth and the exogenic agents i.e., the agents which influence changes on the surface of the Earth, is called Geomorphic processes.

Question 2.
Define Diastrophism.
Answer:
Greek word, dystrophy – meaning distortion. The process of deformation by which the major features of the earth’s crust, including continents, mountains, Ocean beds, folds, and faults, are formed.

Question 3.
Mention the force responsible for Mass movement. Mass movements are directly under the influence of gravity.
Answer:
Transfer of one mass of rock debris down the slopes is the regular activity of mass movement or mass wasting. The term includes a variety of gravity-induced movements of slope material but excludes transportation by running water, wind, glacier etc.

Question 4.
What is Weathering?
Answer:
The process of disintegration and decomposition of rocks is known as “weathering”.

Question 5.
Name any two factors of Mechanical weathering.
Answer:

1. Mechanical Weathering
2. Chemical Weathering

Question 6.
How does granular disintegration occur?
Answer:
Rocks consist of several types of minerals and these minerals react differently to heat. As a result, the rocks break into different mineral grains known as “Granular Disintegration”.

Question 7.
What is the role of oxygen in oxidation?
Answer:
Oxygen in the rain water, reacts with Iron present in rocks and forms Iron oxides.

Question 8.
Which region is predominant in Carbonation?
Answer:
The rain water with carbon-di-oxide becomes a weak carbonic acid and it reacts with calcium carbonate or limestone to form calcium bicarbonate, which dissolves easily. This process is called “Carbonation”. It is very active in limestone regions.

Question 9.
What is River capture?
Answer:
It is formed mainly due to head-ward erosion by the river near its source, when the source of a river is captured by another major and strong river. Eg: The river Testa which was a tributary to the river ganga is now a tributary to river Brahmaputra.

Question 10.
How are ox-bow lakes formed?
Answer:
ox-bow lakes are formed by depositional and erosional actions taking place simultaneously and they are a result of excessive meandering. As the river flows through the shorter route leaving the curve of the meander cut off, a crescent shaped lake is formed.

II. Answer the following in two or three sentences, each.

Question 1.
State the difference between Endogenic and Exogenic forces.
Answer:

1. Endogenic forces: The internal forces which bring the change inside tge Earth. Eg: Volcanoes and Earthquakes.
2. Exogenic forces: The external forces that are found on the surface of the earth, and bring changes through degradation and aggradation processes. Eg- river, glacier, wind, sea waves etc.,

Question 2.
What is Mass movement?
Answer:
Mass Movement or mass wasting is the transfer of one mass of rock debris down the slopes in the regular activity of mass movement is directly influenced by gravity. Gravity produces movements of slope material. The process of mass wasting and the landforms they produce are extremely varied and tend to grade into one another Mass movements depends on

1. kinds of earth materials
2. Kinds of motions that occur
3. physical properties of materials involved.

The important forms of mass movements are rockfall, Talus, Earthflows, mudflows, Land slides, Rockslides.

Question 3.
Name any two types of Weathering processes.
Answer:

• Mechanical Weathering
• Chemical weathering.

Question 4.
Distinguish between Oxidation and Hydration.
Answer:

1. Oxidation: The process in which the oxygen in the rain water, reacts with Iron present in rocks and forms Iron oxides.
2. Hydration: is the process where rock minerals imbibe water and the increased volume creates physical stress with the rock. As a result minerals like feldspar and gypsum are reduced to powder.

Question 5.
How does Biological weathering take place?
Answer:
The disintegration of rocks caused by plants, animals and human beings is called ‘Biological weathering’.

1. Plants: The roots of the plants grow through the soil and in the cracks of rocks to find water and minerals. As the roots grow deep in the rock they widea and disintegrate the rocks. This process is most promineat in thick forests and vegetative regions.
2. Animals: The burrowing animals like rats, rabbits, ants, earth-worms and termites influence in the breaking up of rocks and make passages below the ground. The seepage of air and water through these passages results in rapid weathering of rocks.
3. Human beings: Human beings play an important role in weathering of rocks, through activities like agriculture mining quarring, oil drilling, deforestation etc.

Question 6.
Mention any two agents of denudation.
Answer:

• River
• Underground water

Question 7.
What is Canyon? Give example.
Answer:
The canyon is a deep and steep valley almost with vertical wall like features found in the arid or semi arid regions Eg: Grand canyon of River Colorado in USA.

Question 8.
Distinguish between Meanders and Ox-bow lakes.
Answer:
Meanders is a curve or loop formed by a river in its path, when – it approaches a lower course, the river flows slowly in a Zig-zag as curved manner due to smaller obstruction in its path. The river course forms eresent sheped loops due to continuous lateral deposition.

Question 9.
What is Delta? Name any two types of delta.
Answer:
Delta is a triangular shaped alluvial deposition formed at the mouth of the river Eg: sunder- bans (delta of Ganga and Brahmaputra)

Question 10.
Mention the difference between Tributaries and Distributaries.
Answer:
1. Tributaries:
are a number of streams or small rivers that join a main river. The Thunagabhadra is a tributary of river Krishna.

2. Distributaries:
When a river approaches the sea or ocean, due to reduction in gradient, and joining to tributaries, its volume increases and speed decreases. The river branches up into a number of branches called ‘Distributaries’ Eg: The Hoogly, The Madhu mathi, The Meghana etc are distributaries of the river Ganga.

III. Answer the following.

Question 1.
What is landform? Explain the different types of geomorphic Processes.
Answer:
Landform is and natural formation of rock and dirt, found on the earth. They can be as large as a mountain range or as small as a hill. They are natural features of the landscapes, natural physical features of the earth’s surface Eg -Valleys, Plateaus, mountains, Plains, Hills, Loess, plains, etc., The major landforms of the Earth are:

• Mountains
• Plateaus and
• Plains.

The minor landforms include hills, ridges, valleys, basins etc., According to Geo-Scientists the landforms are formed by the forces acting form the interior and on the surface of the Earth.

Types of Geo-morphicprocesses

1. Endogenic Forces: The internal forces which bring the change inside the Earth like volcanoes and Earth quakes Move elevate or build portions of the Earth’s crust. These include Orogenic or mountain building processes and Eqeirogenic or continental building processes.
2. Exogenic Forces: are external forces found on the surface of the Earth that bring changes through degradation and aggradation processes. Some external forces are rivers, glacier, wind, sea waves etc.,
3. Mass movements: The Gravity of the earth transfer one mass of rock debris down the slopes.

Question 2.
Describe the factors affecting physical weathering.
Answer:
The disintegration of rocks by Mechanical way without any chemical changes is called ‘Physical weathering or Mechanical weathering’ and are influenced by temperature, frost, wind and sea waves.

1. Temperature: High temperature leads the rocks and low temperature contracts them. The continuous process of expansion and contraction during day night and leads to breaking or disintegration of rocks.
2. Frost: The continuous freezing and thawing of the rocks in frigid regions leads to expansion and contraction of rocks and disintegrates them.
3. Wind: The winds blowing over deserts carry sand particles from one region to another and causes friction on the rock surface and scratches and breaks the rocks.
4. Gravitation: The Earths gravity makes the huge rocks to roll down the slopes of mountains and hills. The rocks strike each other and break into pieces.
   Depending on the type of rocks, the mechanical weathering can be described as follows.

(A) Block Disintegration:
Due to variation in temparature the rocks undergo repeated expansions and contraction, which produces stress along joints and finally break down the rocks block by block.

(B) Granular disintegration:
is a process of weathering ofrocks in which the minerals present in the rocks break into different mineral grains due the influence of heat and other natural agents.

(C) Exfoliation:
The differential heating of the rocks exterior surface and the interior expand and cracks the rocks exterior surface similar to the peeling of an onion. This process is called ‘Exfoliation’.

Question 3.
Explain chemical weathering with examples.
Answer:
The disintegration and Decomposition of rocks by chemical processes is called “Chemical Weathering”. During chemical weathering processes secondary or new minerals are developed from the original minerals of the rocks. The rain water and atmospheric gases are the main agents of chemical weathering, and is common is humid regions.
There are four types of chemical weathering processes.

1. Oxidation
2. Carbonation
3. Hydration
4. Solution

1. Oxidation:
The process in which the oxygen in the rain water, reacts with iron present in rocks and forms Iron oxides.

2. Carbonation:
is the process where rain water reacts with carbon-di-oxide to form weak carbonic acid which reacts with calcium carbonate or limestone to form calcium-bi-carbonate, which dissolves easily.

3. Hydration:
is the process where rock minerals imbibe water and the increased volume creates physical stress with the rock. As a result minerals like feldspar and gypsum are reduced to powder.

4. Solution:
is the process where rain water is able to dissolve some of the soluble minerals, used as rock -salt, gypsum, potash.

Question 4.
Describe the landforms associated to work of river.
Answer:
The various landforms associated to the erosional work of rivers are:

1. ‘V’ Shaped valley: When the river courses through mountains its speed is greater and volume of water is less. As the water rushes down the steep slopes there is maximum vertical or lateral erosion. The rapid down cutting or vertical erosion results in the formation of‘V’ Shaped valley.
2. Gorge: is a deep and narrow valley with steep rocky sides in the river course, which are formed by the regular vertical cutting by the rivers in the valleys. Eg Narmada gorge, Gangotri gorge etc.,
3. ‘I’ Shaped valley: is a very steep, deep river valley formed by the river, resembling the english alphabet ‘I’. These are deeper compared to gorges.
4. Canyon: is a deep and steep valley almost with vertical wall like features found in the arid or semi arid regions Eg- Grand canyon of River eolorado in USA.
5. Potholes: are small depressions in the rocky beds of the river valley, formed by corrosion. The pebbles, sand and small rocks carried by rivers swirl around on the river bed and erode the rock on the river bed forming potholes.
6. Waterfalls: are formed when the hard and soft rocks come in the way of flowing river- huge volume of water fall from a great height. The soft rock get eroded fester and hard rock does not erode easily. Therfore huge amount of wafer falls from great height and creates waterfalls.
   Eg: Jogfalls (River Sharavathi), Zambezi (Zambia and Zimbawe).
7. River capture: is formed mainly due to head- ward erosion by the river near its source, when the source of a river is captured by another major and strong river. Eg: The river Testa which was a tribu-tary to the river Ganga is now a tributary to river Brahmaputra.
8. Alluvial fans: When the fast flowing river enters the plateau or plain region it experierience sudden decline in gradient and deposits the light materials in fan shape known as ‘Alluvial fans ’.
9. Alluvial cones: In the plateau and foot hill region when the river spreads out, the eroded materials carried by the river is deposited in conical shape called ‘Alluvial cones ’.
10. Meanders: is a curve or loop formed by a river in its path, when it approaches a lower course, the river flows slowly in a zig-zag or curved manner due to smaller obstruction in its path. The river course forms cresent shaped loops due to continuous lateral deposition.
11. Ox-bow-lakes: are formed by depositional and erosional actions taking place simultaneously and they are a result of excessive meandering. As the river flow through the shorter route leaning the curve of the meander cut off, a creseat shaped lake is formed.
12. Flood plains: When the river is in floods the water over flows on its bank and spreads in the surrounding regions. The silt carricdby the water gets deposited in these areas and creates flat plains on both the banks of the river known as ‘flood plains’
13. Natural Levee: are where the river banks are higher than the flood plains. These Natural levee are formed during floods when the river water crosses its banks and deposits sediments near the banks.
14. Delta: is a triangular shaped alluvial deposition formed at the mouth of the river Eg- Sunderbans (delta of Ganga and Brahmaputra)
15. Estuary: are the tidal mouth of a river having a narrow, gradually widening lay at the mount. At the estuary the river water mixes with the sea water. Eg: Nethravathi Estuary.