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Geomorphic Processes – Class 11 Geography notes, important questions and MCQs

NCERT Class 11 Geography, chapter 5. Notes, key terms, important questions with answers and MCQs.

Chapter overview

The Earth's surface is shaped by geomorphic processes driven by internal (endogenic) and external (exogenic) forces. Endogenic forces, powered by the Earth's internal heat, build up the surface through diastrophism and volcanism. Exogenic forces, powered by the Sun's energy and gravity, wear the surface down through weathering, mass movement, erosion and deposition. Weathering also helps form soils.

Endogenic processes

Diastrophism includes orogeny (mountain building through folding and faulting), epeirogeny (uplift or warping of large areas), earthquakes and plate movements.
Volcanism is the movement of molten rock onto or towards the surface.
Endogenic forces create relief variations that exogenic forces then try to level.

Weathering and mass movement

Weathering is the breaking down of rocks in place; it may be chemical (solution, carbonation, hydration, oxidation and reduction), physical (unloading, temperature changes, freezing and thawing, salt crystallisation) or biological.
Mass movements are the movement of rock and debris down slopes under gravity; they include slow movements such as creep and solifluction and rapid movements such as earthflow, mudflow, landslides, slumps and rockfalls.
Weathering is important for soil formation, enrichment of ores and erosion.

Erosion, deposition and soil formation

Erosion is the removal and transport of rock debris by agents such as running water, groundwater, glaciers, wind and waves; deposition follows when agents lose energy.
Soil is formed by the action of five factors: parent material, topography, climate, biological activity and time.
Denudation is the overall wearing down of the land by weathering, mass movement, erosion and transport.

Key terms

Endogenic forces: internal forces that build up the Earth's surface
Exogenic forces: external forces that wear down the Earth's surface
Weathering: breaking down of rocks in place by physical, chemical or biological processes
Mass movement: downslope movement of rock and debris under gravity
Denudation: wearing down of the land surface by exogenic processes

Important questions with answers

What is the difference between weathering and erosion?2 marks

Weathering is the breaking down of rocks in place by physical, chemical or biological processes without movement. Erosion is the removal and transport of the weathered material by agents such as running water, wind, glaciers and waves.

What are mass movements? Give examples.3 marks

Mass movements are the movements of rock and soil debris down slopes under the direct influence of gravity, without a transporting agent carrying them. Slow movements include creep and solifluction, while rapid movements include earthflows, mudflows, debris avalanches, landslides, slumps and rockfalls.

Explain endogenic and exogenic geomorphic processes.5 marks

Geomorphic processes are the physical and chemical processes that shape the Earth's surface. Endogenic processes are driven by energy from within the Earth, mainly radioactivity, rotational and tidal friction and primordial heat. They include diastrophism, which covers orogeny or mountain building through severe folding and faulting, epeirogeny or the uplift and warping of large parts of the crust, earthquakes and plate tectonics, and volcanism, the movement of molten rock towards and onto the surface. These processes create differences in relief. Exogenic processes are driven by solar energy and gravity, acting through agents such as running water, wind, glaciers, waves and groundwater. They include weathering, which breaks rocks down in place through physical, chemical and biological processes; mass movement, in which debris moves downslope under gravity; erosion, in which agents remove and transport material; and deposition, in which material is laid down when agents lose energy. Together these exogenic processes, called denudation, wear down high areas and fill low areas, while endogenic processes keep creating new relief. The balance between them shapes the landscapes we see.

Quick revision

Endogenic: diastrophism and volcanism.
Exogenic: weathering, mass movement, erosion, deposition.
Weathering: chemical, physical, biological.
Soil: parent material, topography, climate, organisms, time.

Exam tips

Make two columns: endogenic and exogenic processes.
Learn the five soil-forming factors.

Practice MCQs

Forces that originate within the Earth are called
1. exogenic forces
2. endogenic forces
3. solar forces
4. tidal forces
Show answer
Answer: (b) endogenic forces. They build up relief.
Breaking down of rocks in place is called
1. erosion
2. deposition
3. transport
4. weathering
Show answer
Answer: (d) weathering. No movement of material is needed.
Which is an agent of erosion
1. granite
2. running water
3. basalt
4. clay
Show answer
Answer: (b) running water. Water carries away debris.
Mountain building through folding and faulting is called
1. epeirogeny
2. solifluction
3. denudation
4. orogeny
Show answer
Answer: (d) orogeny. It is part of diastrophism.
The very slow downslope movement of soil is called
1. rockfall
2. landslide
3. creep
4. avalanche
Show answer
Answer: (c) creep. It can tilt fences and poles.
Oxidation of iron-bearing rocks is a type of
1. physical weathering
2. mass movement
3. biological weathering
4. chemical weathering
Show answer
Answer: (d) chemical weathering. It produces reddish colours.
Which factor is NOT one of the five soil-forming factors
1. latitude of the capital city
2. climate
3. time
4. parent material
Show answer
Answer: (a) latitude of the capital city. Topography and organisms are the others.
Why do exogenic processes vary from place to place
1. they depend only on rock colour
2. they are the same everywhere
3. climate, relief, rock type and vegetation affect them
4. they are caused only by earthquakes
Show answer
Answer: (c) climate, relief, rock type and vegetation affect them. Temperature and rainfall matter most.

All chapters of Class 11 Geography

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.