CBSE Class 11 Geography Chapter 11: Water in the Atmosphere NCERT Solutions

Reviewed by NCERT Help Editorial Team · Updated on 29 Jul 2026

NCERT Solutions PDF Class 11 PDF

This chapter, "Water in the Atmosphere," delves into the crucial role of water in Earth's atmospheric processes. It covers the fundamental concepts of atmospheric moisture, including water vapor, its sources, and its distribution. The solutions explain the processes of evaporation and transpiration, which are vital for introducing water vapor into the atmosphere. Key concepts like relative humidity, absolute humidity, and saturated air are clarified, along with the factors influencing them. The chapter also details the formation of clouds and their classification based on altitude and appearance, such as cirrus, cumulus, stratus, and nimbus. Finally, it discusses the world distribution of precipitation, highlighting different rainfall regimes. These NCERT Solutions provide clear, step-by-step explanations and detailed answers to help students grasp these essential geographical concepts, aiding in effective exam revision.

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Quick info

Board	CBSE
Class	Class 11
Subject	Geography
Session	2026
Language	English
Type	NCERT Solutions
Chapter	11. Water in the Atmosphere

Chapter summary

Chapter 11, "Water in the Atmosphere," focuses on the significance of atmospheric water. The NCERT Solutions cover the essential components of atmospheric moisture, the processes of evaporation and transpiration, and the different measures of humidity. It also explains cloud formation and classification, and the global patterns of precipitation. These solutions are designed to provide a thorough understanding of the chapter's content, preparing students for examinations.

Learning outcomes

Identify the most important atmospheric constituent for human beings.
Understand the process of evaporation and its role in transforming liquid into vapor.
Define and differentiate between various types of humidity.
Recognize the highest type of cloud found in the sky.
Name and describe the different forms of precipitation.
Explain the concept of relative humidity and its significance.
Analyze the reasons for the rapid decrease of water vapor with altitude.
Describe the process of cloud formation and their classification.

Topics covered

Paper topics

Water Vapour
Evaporation
Transpiration
Humidity (Absolute, Specific, Relative)
Saturated Air
Cloud Formation
Cloud Classification (Cirrus, Cumulus, Stratus, Nimbus)
Precipitation
Types of Precipitation (Rainfall, Snowfall, Sleet)
World Distribution of Precipitation

Important topics

Humidity and its types
Cloud formation and classification
Processes of Evaporation and Transpiration
Factors affecting water vapor with altitude
Types and distribution of precipitation

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Questions and Solutions

Multiple-choice questions

1. Which one of the following is the most important constituent of the atmosphere for human beings?

Water vapour
Nitrogen
Dust particle
Oxygen

Solution: The atmosphere contains various gases and particles, but water vapour plays a critical role in supporting life. It is essential for weather phenomena like rainfall, which is vital for all living organisms, and it also influences temperature regulation. Therefore, water vapour is considered the most important constituent for human beings among the given options.

Answer: (a) Water vapour

2. Which one of the following process is responsible for transforming liquid into vapour?

Condensation
Transpiration
Evaporation
Precipitation

Solution: Evaporation is the fundamental process where a liquid substance changes into a gaseous state (vapour). This occurs when the molecules in the liquid gain enough energy, typically from heat, to overcome the intermolecular forces holding them together and escape into the surrounding atmosphere as vapour.

Answer: (c) Evaporation

3. The air that contains moisture to its full capacity:

Relative humidity
Specific humidity
Absolute humidity
Saturated air

Solution: Saturated air refers to the condition where the atmosphere holds the maximum amount of water vapour possible at a specific temperature and pressure. If more water vapour is added or the temperature drops, the excess moisture will condense into liquid water or ice.

Answer: (d) Saturated air

4. Which one of the following is the highest cloud in the sky?

Cirrus
Stratus
Nimbus
Cumulus

Solution: Cirrus clouds are high-level clouds, typically found at altitudes above 6,000 meters (20,000 feet). They are composed primarily of ice crystals due to the cold temperatures at these heights and often appear thin, wispy, and feathery.

Answer: (a) Cirrus

Answer the following questions in about 30 words

(i) Name the three types of precipitation.

Solution: Precipitation refers to any form of water that falls from the atmosphere to the Earth's surface. The three primary types commonly recognized are rainfall, which is liquid water droplets; snowfall, which consists of ice crystals; and sleet, which is a mixture of rain and ice pellets.

Answer: Three types of precipitation are: rainfall, snowfall, and sleet.

(ii) Explain relative humidity.

Solution: Relative humidity is a measure that expresses the amount of water vapour present in the air as a percentage of the maximum amount the air could hold at that specific temperature. A higher relative humidity indicates that the air is closer to its saturation point.

Answer: Relative humidity is the percentage of moisture present in the atmosphere compared to its maximum capacity at a given temperature. A higher percentage signifies more humid air.

(iii) Why does the amount of water vapour decrease rapidly with altitude?

Solution: The primary sources of atmospheric water vapour are evaporation from water bodies and transpiration from plants. Both these processes are temperature-dependent, and temperature generally decreases with increasing altitude in the troposphere. Consequently, the rate of evaporation and the air's capacity to hold water vapour diminish significantly as one ascends, leading to a rapid decrease in water vapour content.

Answer: The amount of water vapour decreases rapidly with altitude because evaporation rates and air temperature, which dictates water vapour holding capacity, both decrease with increasing altitude in the troposphere.

(iv) How are clouds formed? Classify them.

Solution: Clouds form when water vapour in the atmosphere cools and condenses into tiny water droplets or ice crystals around microscopic particles (like dust or salt). These suspended droplets or crystals form visible masses. Clouds are classified based on their altitude and appearance into four main types: cirrus (high, wispy), cumulus (puffy, detached), stratus (layered, sheet-like), and nimbus (rain-bearing).

Answer: Clouds are formed by the condensation of water vapour in the air at considerable elevations, creating masses of minute water droplets or ice crystals. They are classified into four main types: cirrus, cumulus, stratus, and nimbus, based on their height, expanse, density, and transparency.

Answer the following questions in about 150 words

(i) Discuss the salient features of the world distribution of precipitation.

Solution: The world distribution of precipitation, primarily rainfall, is highly variable across different regions. Areas near the equator, influenced by the Inter-Tropical Convergence Zone (ITCZ), generally receive high rainfall throughout the year. Mid-latitude regions experience seasonal variations, often with distinct wet and dry periods, influenced by the movement of pressure belts and storm tracks. Deserts, typically located around 30° N and S latitudes, receive very low precipitation due to descending dry air masses. Mountainous regions show significant variations, with windward slopes receiving much more rainfall than leeward slopes (rain shadow effect). Polar regions receive minimal precipitation, often in the form of snow, due to low temperatures and limited atmospheric moisture. Coastal areas may receive more precipitation than inland areas due to proximity to moisture sources.

Answer: The world distribution of precipitation is characterized by significant regional variations. Equatorial regions and windward mountain slopes generally receive abundant rainfall. Mid-latitudes experience seasonal precipitation patterns. Deserts, located around 30° N and S, are arid with very low rainfall due to descending dry air. Polar regions receive minimal precipitation, often as snow. Leeward mountain slopes and continental interiors tend to be drier.

Common mistakes

Confusing different types of humidity (relative, specific, absolute).
Misidentifying the highest cloud type.
Not fully explaining the factors affecting water vapor decrease with altitude.
Incomplete classification or description of clouds and precipitation.

Revision tips

Focus on understanding the definitions and differences between various humidity types.
Memorize the different types of precipitation and clouds, along with their characteristics.
Pay close attention to the explanation of why water vapor decreases with altitude.
Review the world distribution of precipitation to understand global patterns.

Practice MCQs

Q1. Which atmospheric constituent is most vital for human existence?

Q2. What is the process by which a liquid changes into a gas or vapor?

Q3. Air that holds the maximum possible amount of moisture at a given temperature is called:

Q4. Which type of cloud is typically found at the highest altitudes in the sky?

Q5. Which of the following is NOT a primary type of precipitation?

Frequently asked questions

What is the most important constituent of the atmosphere for human beings according to the chapter?

According to the chapter, water vapour is the most important constituent of the atmosphere for human beings.

What process transforms liquid into vapor?

The process responsible for transforming liquid into vapor is evaporation.

What is saturated air?

Saturated air is air that contains moisture to its full capacity at a given temperature.

Which are the three main types of precipitation mentioned?

The three main types of precipitation mentioned are rainfall, snowfall, and sleet.

Why does water vapor decrease rapidly with altitude?

Water vapor decreases rapidly with altitude because both evaporation and temperature, which determine water vapor holding capacity, decrease as altitude increases in the troposphere.

How are clouds classified in this chapter?

Clouds are classified into four main types based on their height, expanse, density, and transparency: cirrus, cumulus, stratus, and nimbus.

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