NCERT Solutions for Class 11 Geography Chapter 6: Landforms and Their Evolution (NCERT 2026–27)

These Class 11 Geography Chapter 6 solutions cover Landforms and Their Evolution from the NCERT textbook Fundamentals of Physical Geography, updated for the 2026–27 session. The chapter explains how the major geomorphic agents — running water, groundwater, glaciers, waves and currents, and winds — sculpt the earth’s surface, producing distinctive erosional and depositional landforms that pass through stages of youth, maturity and old age. Below you will find step-by-step answers to all the NCERT exercise questions (reproduced verbatim), plus key terms, extra practice, MCQs, Assertion–Reason questions and FAQs.

Class: 11 Subject: Geography Book: Fundamentals of Physical Geography Chapter: 6 Chapter Name: Landforms and Their Evolution Session: 2026–27
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Class 11 Geography Chapter 6 – Overview

After weathering breaks down rock at the surface, the geomorphic agents — running water, groundwater, glaciers, waves and currents, and winds — carry out erosion followed by deposition, continually changing the land. Every landform has a history of development, and a landmass passes through stages comparable to youth, maturity and old age. Running water dominates in humid regions, carving valleys, gorges, canyons, potholes and meanders and building alluvial fans, floodplains, levees and deltas. Groundwater dissolves limestone to create Karst topography (sinkholes, caves, lapies, stalactites and stalagmites). Glaciers grind out cirques, horns, arêtes and U-shaped valleys and deposit moraines, eskers, outwash plains and drumlins. Waves and currents shape cliffs, sea caves, stacks, beaches, bars and spits along coasts, while winds in deserts produce pediments, playas, mushroom rocks and various sand dunes. Understanding these processes helps explain the variety of landscapes on the earth’s surface.

Key Concepts & Terms

Landform & landscape: a small to medium tract of the earth’s surface is a landform; several related landforms together make up a landscape (a large tract of the surface).

Evolution of landforms: the stages of transformation of the surface from one landform into another (or change in an individual landform after it forms), passing through youth, mature and old stages.

Stages of a river valley — Youth, Mature, Old: in youth, streams are few with V-shaped valleys, waterfalls and broad divides; in maturity, valleys are deep V-shapes with wide floodplains and meanders, waterfalls disappear; in old age, rivers meander freely over vast floodplains with levees and oxbow lakes near sea level.

Running-water erosional landforms: valleys, gorges, canyons, potholes, plunge pools, incised (entrenched) meanders and river terraces.

Running-water depositional landforms: alluvial fans, deltas, floodplains, natural levees, point bars and meanders (a channel pattern, not a landform).

Karst topography: landforms produced by groundwater solution and deposition in limestone/dolomite — swallow holes, sinkholes, dolines, uvalas (valley sinks), lapies, limestone pavements and caves; deposition forms stalactites, stalagmites and pillars.

Glacial erosional landforms: cirques (tarn lakes), horns, arêtes (serrated ridges), U-shaped glacial valleys, hanging valleys and fjords.

Glacial depositional landforms: moraines (terminal, lateral, medial, ground), eskers, outwash plains and drumlins (formed of glacial till).

Coastal landforms: high rocky (submerged) coasts show cliffs, wave-cut terraces, sea caves and stacks; low sedimentary (emerged) coasts build beaches, dunes, bars, barrier bars, spits and lagoons.

Desert (wind) landforms: pediments and pediplains, playas, deflation hollows, mushroom/table/pedestal rocks (erosional); sand dunes such as barchans, parabolic, seif, longitudinal and transverse (depositional).

NCERT Exercises — Full Solutions

All questions below are reproduced verbatim from the NCERT textbook’s end-of-chapter Exercises. Answers are original, written in CBSE exam-ready style.

1. Multiple choice questions.

(i) In which of the following stages of landform development, downward cutting is dominated? (a) Youth stage    (c) Early mature stage (b) Late mature stage    (d) Old stage

ANSWER (a) Youth stage. In the youthful stage streams flow over original, steep slopes, so down-cutting (vertical erosion) dominates as the river deepens its bed. Lateral erosion and wide floodplains develop only later in the mature and old stages.

(ii) A deep valley characterised by steep step-like side slopes is known as (a) U-shaped valley    (c) Blind valley (b) Gorge    (d) Canyon

ANSWER (d) Canyon. A canyon is characterised by steep, step-like side slopes and is wider at its top than at its bottom. It commonly forms in horizontally bedded sedimentary rocks. (A gorge, by contrast, is nearly equal in width at top and bottom.)

(iii) In which one of the following regions the chemical weathering process is more dominant than the mechanical process? (a) Humid region    (c) Arid region (b) Limestone region    (d) Glacier region

ANSWER (b) Limestone region. In limestone (and dolomite) regions, rocks rich in calcium carbonate are dissolved by the chemical processes of solution and precipitation. This chemical weathering dominates over mechanical processes and produces Karst landforms.

(iv) Which one of the following sentences best defines the term ‘Lapies’? (a) A small to medium sized shallow depression (b) A landform whose opening is more or less circular at the top and funnel shaped towards bottom (c) A landform formed due to dripping water from surface (d) An irregular surface with sharp pinnacles, grooves and ridges

ANSWER (d) An irregular surface with sharp pinnacles, grooves and ridges. Lapies form when most of a limestone surface is eaten away by pits and trenches through differential solution along joints, leaving an extremely irregular surface of points, grooves and ridges. (Option (b) describes a sinkhole and option (c) a stalactite.)

(v) A deep, long and wide trough or basin with very steep concave high walls at its head as well as in sides is known as: (a) Cirque    (c) Lateral Moraine (b) Glacial valley    (d) Esker

ANSWER (a) Cirque. A cirque is a deep, long and wide trough or basin with very steep concave to vertically dropping high walls at its head and sides, cut by accumulated ice at the head of a glacial valley. A lake within it after the ice melts is called a cirque or tarn lake.

2. Answer the following questions in about 30 words.

(i) What do incised meanders in rocks and meanders in plains of alluvium indicate?

ANSWER Meanders in alluvial plains indicate a river flowing leisurely over very gentle gradients and working laterally on soft banks. Incised (entrenched) meanders cut deep in hard rocks indicate uplift of land or rejuvenation, forcing the meandering river to cut vertically.

(ii) Explain the evolution of valley sinks or uvalas.

ANSWER When several sinkholes and dolines join together — because of the slumping of materials along their margins or the collapse of cave roofs — they form long, narrow to wide trenches called valley sinks or uvalas. They mark a stage of advanced solution erosion of limestone.

(iii) Underground flow of water is more common than surface run-off in limestone areas. Why?

ANSWER Limestone is highly permeable, jointed and cracked, and is easily dissolved by carbonated water. Surface water quickly seeps down through swallow holes, sinkholes, joints and bedding planes and flows as underground streams, so underground flow exceeds surface run-off.

(iv) Glacial valleys show up many linear depositional forms. Give their locations and names.

ANSWER Linear depositional forms of glacial till are moraines: terminal moraines at the toe (end) of the glacier, lateral moraines along the sides parallel to the valley, medial moraine in the centre between two lateral moraines, and ground moraines spread over the valley floor. Eskers are sinuous ridges on the valley floor.

(v) How does wind perform its task in desert areas? Is it the only agent responsible for the erosional features in the deserts?

ANSWER Wind works through deflation (lifting and removing loose dust and sand), abrasion (sand-blasting rock surfaces) and impact. But it is not the only agent — mass wasting and running water as sheet floods (from torrential desert rains) also do major erosion, removing weathered debris.

3. Answer the following questions in about 150 words.

(i) Running water is by far the most dominating geomorphic agent in shaping the earth’s surface in humid as well as in arid climates. Explain.

ANSWER In humid regions, which receive heavy rainfall, running water is the most important geomorphic agent in degrading the land surface. It works through two components — overland flow (sheet erosion across the land) and linear flow as streams and rivers in valleys. Youthful rivers on steep gradients cut downward, forming rills, gullies, valleys, gorges, canyons, waterfalls and potholes; as gradients gentle, lateral erosion and deposition build floodplains, meanders, levees, alluvial fans and deltas, eventually reducing the land to a peneplain. In arid regions, although rain is scarce it falls torrentially in short bursts. The desert rocks, devoid of vegetation, decay fast through weathering, and the weathered debris is moved mainly by sheet floods and sheet wash, not by wind alone. General mass erosion and the extension of pediments are accomplished chiefly by running water. Thus running water dominates landform shaping in both humid and arid climates.

(ii) Limestones behave differently in humid and arid climates. Why? What is the dominant and almost exclusive geomorphic process in limestone areas and what are its results?

ANSWER Limestones and dolomites are rich in calcium carbonate, which is readily dissolved by carbonated (carbon-dioxide-rich) water. In humid climates, abundant rainfall and surface water keep the processes of solution and precipitation active, so limestone is heavily dissolved and Karst landforms develop. In arid climates, water is scarce, so solution is limited and limestone is comparatively resistant and behaves like other hard rocks; here mechanical processes dominate. The dominant and almost exclusive geomorphic process in limestone areas is the chemical process of solution and precipitation (deposition) by surface water and groundwater. Its results are Karst topography: erosional forms such as swallow holes, sinkholes, dolines, uvalas (valley sinks), lapies, limestone pavements and caves; and depositional forms such as stalactites, stalagmites and pillars formed inside caves where calcium carbonate is re-deposited as water evaporates.

(iii) How do glaciers accomplish the work of reducing high mountains into low hills and plains?

ANSWER Glaciers are masses of ice that move slowly down slopes or spread as sheets under the force of gravity. Their erosion is tremendous because of the friction caused by the sheer weight of the ice. As a glacier moves, it carries large angular blocks and rock debris that get dragged along the floor and sides of the valley, causing great damage through abrasion and plucking. In this way glaciers can damage even un-weathered, hard rocks. Continued movement removes debris, lowers the divides and deepens and widens the valleys into U-shapes, carving cirques, horns and arêtes at the heights. Gradually the slope is reduced so much that the glacier finally stops moving, leaving behind a mass of low hills and vast outwash plains together with moraines, eskers and drumlins. Thus glaciers grind high mountains down into low hills and plains.

Extra Practice Questions

Short Answer Type Questions

Q1. Distinguish between a gorge and a canyon.

ANSWERA gorge is a deep valley with very steep to straight sides and is almost equal in width at its top and bottom; it forms in hard rocks. A canyon has steep, step-like side slopes and is wider at its top than its bottom; it forms in horizontally bedded sedimentary rocks. A canyon is a variant of a gorge.

Q2. What are potholes and plunge pools?

ANSWERPotholes are more or less circular depressions over the rocky beds of hill-streams, formed by stream erosion aided by the abrasion of rotating rock fragments. Large, deep potholes at the base of waterfalls, formed by the sheer impact of falling water and rotation of boulders, are called plunge pools.

Q3. How is a delta different from an alluvial fan?

ANSWERBoth are depositional cones, but an alluvial fan forms where a stream from higher levels breaks onto foot-slope plains, with poorly sorted coarse load. A delta forms where a river dumps its load into the sea; its deposits are very well sorted with clear stratification, and distributaries extend as the delta builds into the sea.

Q4. What is an oxbow lake and how does it form?

ANSWERAn oxbow lake is a curved, cut-off loop of a river left on a floodplain. As meanders grow into deep loops through deposition on the convex bank and undercutting on the concave bank, the loop is finally cut off by erosion at the inflection points, leaving an isolated crescent-shaped lake.

Q5. Name and describe any two types of sand dunes.

ANSWERBarchans are crescent-shaped dunes whose wings point downwind; they form where the wind direction is constant and moderate over a uniform surface. Longitudinal dunes are long, low ridges that form when sand supply is poor and the wind direction is constant; they lie parallel to the wind direction.

Long Answer Type Questions

Q1. Describe the erosional landforms produced by running water.

ANSWERRunning water produces several erosional landforms. Valleys begin as rills, which deepen and widen into gullies and then valleys; depending on shape they may be V-shaped valleys, gorges or canyons. Potholes are circular depressions cut into rocky stream beds by abrasion, and large potholes at the foot of waterfalls become plunge pools. Incised or entrenched meanders are deep, wide meanders cut into hard rocks, indicating uplift of the land. River terraces are surfaces marking old valley-floor or floodplain levels; they result from vertical erosion of a river into its own floodplain, and when found at the same height on both banks they are called paired terraces. Together these forms show how a youthful river deepens and reshapes its course mainly through vertical and lateral erosion.

Q2. Explain the evolution of coastal landforms along high rocky coasts and low sedimentary coasts.

ANSWERAlong high rocky (submerged) coasts, drowned river valleys give a highly irregular, indented coastline, and waves break with great force, shaping hillsides into cliffs. As cliffs recede, a wave-cut platform forms in front, hollows widen into sea caves, and resistant remnants stand as sea stacks. With time, deposition offshore builds a wave-built terrace, and beaches and bars develop; erosional forms dominate, as on India’s west coast. Along low sedimentary (emerged) coasts, rivers build coastal plains and deltas and the shoreline is smooth. Breaking waves churn bottom sediments to build beaches, sand dunes, offshore bars, barrier bars, spits and lagoons; lagoons gradually fill to form coastal plains. Depositional forms dominate, as on India’s east coast. Storm and tsunami waves can rapidly alter both coast types.

Q3. Discuss the erosional and depositional landforms associated with glaciers.

ANSWERErosional landforms: Cirques are deep basins with steep walls at the heads of glacial valleys, often holding tarn lakes. Horns are sharp peaks formed where several cirques erode headward and meet (e.g., the Matterhorn, Everest), and the narrow divides between them become serrated ridges or arêtes. Glacial valleys are U-shaped troughs with broad floors and steep sides; tributary hanging valleys and, where filled with sea water, fjords also form. Depositional landforms: the unsorted till dropped by melting ice forms moraines (terminal, lateral, medial and ground). Eskers are sinuous ridges deposited by sub-glacial streams; outwash plains are broad, sorted glacio-fluvial deposits beyond the ice; and drumlins are smooth, oval till mounds whose long axes show the direction of ice movement, with a blunt stoss end and a tapering tail.

MCQs & Assertion–Reason

1. The almost plain surface left at the end of stream erosion, with low resistant remnants called monadnocks, is a:

(a) pediplain    (b) peneplain    (c) floodplain    (d) outwash plain

2. A meander is best described as a:

(a) depositional landform    (b) type of channel pattern    (c) erosional landform    (d) coastal landform

3. Karst topography is named after a region adjacent to the:

(a) Mediterranean Sea    (b) Black Sea    (c) Adriatic Sea    (d) Caspian Sea

4. Icicle-like depositional forms that hang from the roof of a limestone cave are called:

(a) stalagmites    (b) stalactites    (c) pillars    (d) lapies

5. Very deep glacial troughs filled with sea water along high-latitude shorelines are called:

(a) hanging valleys    (b) cirques    (c) fjords    (d) arêtes

6. The blunter, steeper end of a drumlin that faces the glacier is called the:

(a) tail    (b) stoss end    (c) snout    (d) crest

7. A barrier bar that gets keyed up to the headland of a bay is called a:

(a) spit    (b) lagoon    (c) sea stack    (d) beach

8. A shallow desert lake in which water is retained only for a short time and which often contains salt deposits is a:

(a) pediment    (b) playa    (c) inselberg    (d) deflation hollow

9. An isolated remnant of a mountain left standing on a pediplain in a desert is an:

(a) inselberg    (b) esker    (c) monadnock    (d) horn

10. Low, linear, parallel ridges of coarse deposits found along the banks of large rivers are:

(a) point bars    (b) natural levees    (c) terraces    (d) distributaries

Answer key: 1-(b), 2-(b), 3-(c), 4-(b), 5-(c), 6-(b), 7-(a), 8-(b), 9-(a), 10-(b).

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: In the youthful stage of a river, downward cutting dominates.

Reason: Youthful streams flow over original steep slopes, so vertical erosion is most active.

A-R 2. Assertion: A meander is a landform.

Reason: A meander is only a loop-like channel pattern caused by lateral working of water, coriolis force and unconsolidated banks.

A-R 3. Assertion: Karst landforms develop mainly in limestone and dolomite regions.

Reason: Limestone and dolomite are rich in calcium carbonate, which is easily dissolved by carbonated water.

A-R 4. Assertion: Drumlins indicate the direction of glacier movement.

Reason: The long axes of drumlins are parallel to the direction of ice movement, with a blunt stoss end facing the glacier.

A-R 5. Assertion: Wind is the only agent responsible for erosional features in deserts.

Reason: Sheet floods and running water from torrential desert rains also accomplish major erosion in deserts.

Answer key: 1-(A), 2-(D), 3-(A), 4-(A), 5-(D).

Exam Tips & Common Mistakes

How to score full marks in this chapter

Organise your revision agent-wise (running water, groundwater, glaciers, waves, winds) and, under each, list erosional and depositional landforms separately — examiners often ask you to classify or distinguish them. Memorise the three river stages (youth, mature, old) with their key features. For distinguish questions (gorge vs canyon, till vs alluvium, glacial vs river valley, levee vs point bar), use a two-column comparison with one example each. Always link a landform to the process that makes it (abrasion, plucking, solution, deposition). Quote textbook examples — Matterhorn/Everest as horns, India’s west coast (erosional) and east coast (depositional) — to show depth.

Common mistakes to avoid

  • Calling a meander a “landform” — it is a channel pattern, not a landform.
  • Confusing stalactites (hang from the roof) with stalagmites (rise from the floor).
  • Mixing up a gorge (equal width top and bottom) with a canyon (wider at top, step-like sides).
  • Swapping cirque, horn and arête, or confusing the four types of moraines (terminal, lateral, medial, ground).
  • Assuming wind is the only desert agent — sheet floods and running water do major work too.
  • Confusing a peneplain (stream erosion) with a pediplain (desert erosion) or an outwash plain (glacial).

Frequently Asked Questions

What is Chapter 6 of Class 11 Geography (Fundamentals of Physical Geography) about?

Chapter 6, Landforms and Their Evolution, explains how geomorphic agents — running water, groundwater, glaciers, waves and currents, and winds — carry out erosion and deposition to produce distinctive erosional and depositional landforms, and how landmasses evolve through stages of youth, maturity and old age.

What are the two main aspects of the evolution of landforms?

The two important aspects are erosion (the wearing away and transformation of the surface from one landform to another) and deposition (the building of new landforms from transported material). Together they change individual landforms and the wider landscape through time.

What is the difference between erosional and depositional landforms in this chapter?

Erosional landforms (such as valleys, gorges, cirques, sinkholes, cliffs and pediments) are carved out when an agent removes material, while depositional landforms (such as deltas, alluvial fans, moraines, beaches, spits and sand dunes) are built up when the agent dumps the material it was carrying.

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