CBSE Class 11 Fundamental of Physical 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 vapor in Earth's atmosphere. The NCERT Solutions provide clear explanations and answers to key concepts, including the primary constituents of the atmosphere vital for life, the process of evaporation, and the definition of saturated air. It also covers the classification of clouds based on their altitude and appearance, such as cirrus, cumulus, stratus, and nimbus. Furthermore, the solutions detail the different forms of precipitation like rainfall, snowfall, and sleet, and explain why water vapor content diminishes with increasing altitude. The chapter concludes with a discussion on the global distribution patterns of precipitation. These solutions are designed to help students grasp complex atmospheric processes, clarify doubts, and prepare effectively for their examinations by offering detailed, step-by-step explanations.

Home

Quick info

Board	CBSE
Class	Class 11
Subject	Fundamental of Physical Geography
Session	2026
Language	English
Type	NCERT Solutions
Chapter	Chapter 11

Chapter summary

Chapter 11, "Water in the Atmosphere," focuses on the essential components and processes related to atmospheric moisture. The NCERT Solutions cover multiple-choice questions on atmospheric constituents, evaporation, humidity, and cloud types. It also addresses short-answer questions on precipitation types, relative humidity, the decrease of water vapor with altitude, and cloud formation and classification. Finally, it includes a long-answer question discussing the world distribution of precipitation. This chapter is crucial for understanding weather phenomena.

Learning outcomes

Identify the most important atmospheric constituent for human beings.
Explain the process of evaporation and its role in transforming liquid into vapor.
Define saturated air and understand the concept of humidity.
Classify different types of clouds based on their characteristics.
List and describe the various forms of precipitation.
Explain the reasons for the decrease in water vapor with altitude.
Discuss the global distribution patterns of precipitation.

Topics covered

Paper topics

Atmospheric Constituents
Water Vapour
Evaporation
Condensation
Humidity (Relative, Specific, Absolute)
Saturated Air
Clouds (Classification: Cirrus, Cumulus, Stratus, Nimbus)
Precipitation (Rainfall, Snowfall, Sleet)
Water Vapour Decrease with Altitude
Global Distribution of Precipitation

Important topics

Cloud Formation and Classification
Types and Distribution of Precipitation
Understanding Humidity and Saturated Air
Factors Affecting Water Vapour Content in the Atmosphere

PDF preview

Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.

Loading document …

Page of

Loading page …

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, but oxygen is indispensable for the survival of most living organisms, including humans, as it is required for respiration. While water vapour and nitrogen are also crucial components, oxygen's direct role in sustaining life makes it the most important constituent for human beings.

Answer: (d) Oxygen

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

Condensation
Transpiration
Evaporation
Precipitation

Solution: Evaporation is the process by which a liquid changes into a gas or vapor. This occurs when the molecules in a liquid gain enough energy, typically from heat, to overcome the intermolecular forces holding them together and escape into the atmosphere as gas. Condensation is the opposite process, precipitation is water falling from the atmosphere, and transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers.

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 air holds the maximum amount of water vapor possible at a specific temperature and pressure. At this point, the air cannot absorb any more moisture, and the rate of evaporation equals the rate of condensation. Relative humidity measures the current amount of water vapor in the air compared to the maximum it can hold, specific humidity is the mass of water vapor per unit mass of moist air, and absolute humidity is the mass of water vapor per unit volume of air.

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, white, and wispy. Stratus clouds are low-level, gray, and featureless, while cumulus clouds are detached, puffy clouds with flat bases, and nimbus clouds are rain-producing clouds.

Answer: (a) Cirrus

Answer the following questions in about 30 words

(i) Name the three types of precipitation.

Solution: Precipitation is any form of water that falls from the atmosphere to the Earth's surface. The three primary types of precipitation are rainfall, which consists of liquid water droplets; snowfall, which consists of ice crystals; and sleet, which is a form of precipitation consisting of ice pellets, often mixed with rain or snow.

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

(ii) Explain relative humidity.

Solution: Relative humidity is a measure of the amount of water vapor present in the air compared to the maximum amount of water vapor the air can hold at a specific temperature. It is usually expressed as a percentage. A higher relative humidity indicates that the air is closer to its saturation point and feels more humid.

Answer: Relative humidity is the percentage of moisture present in the atmosphere compared to its full capacity at a given temperature.

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

Solution: The amount of water vapor in the atmosphere decreases rapidly with altitude primarily because the sources of water vapor, such as evaporation from water bodies and transpiration from plants, are concentrated near the Earth's surface. Furthermore, atmospheric temperature generally decreases with increasing altitude in the troposphere, reducing the air's capacity to hold water vapor. Consequently, both the availability of moisture and the air's holding capacity diminish as one ascends.

Answer: Water vapor decreases rapidly with altitude because evaporation and temperature, which determine water vapor holding capacity, decrease with increasing altitude in the troposphere.

(iv) How are clouds formed? Classify them.

Solution: Clouds are formed when water vapor in the atmosphere cools and condenses into tiny water droplets or ice crystals around microscopic particles (like dust or salt) in the air. This condensation typically occurs at considerable elevations where temperatures are lower. Clouds are broadly classified based on their height, appearance, and density into four main types: cirrus (high, wispy, ice crystals), cumulus (puffy, detached, with flat bases), stratus (flat, gray layers), and nimbus (rain-bearing clouds, often appearing dark and dense).

Answer: Clouds form from the condensation of water vapor at high altitudes. They are classified into four main types: cirrus, cumulus, stratus, and nimbus.

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 is highly variable, influenced by factors such as latitude, proximity to oceans, prevailing winds, and mountain ranges. Generally, equatorial regions receive high rainfall due to convectional processes. Coastal areas influenced by onshore winds also experience significant precipitation. Conversely, continental interiors and regions in the rain shadow of mountains tend to be drier. Deserts are characterized by extremely low precipitation. Temperate regions show seasonal variations, with some experiencing wet summers and dry winters, while others have more evenly distributed rainfall throughout the year. High-latitude areas often receive precipitation in the form of snow. The distribution is not uniform, leading to distinct wet and dry climate zones across the globe.

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 of clouds or precipitation types.

Revision tips

Focus on understanding the definitions of key terms like evaporation, condensation, and saturation.
Memorize the different types of clouds and precipitation and their characteristics.
Pay close attention to the explanation of why water vapor decreases with height.
Review the global distribution of precipitation to understand regional variations.

Practice MCQs

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

Q2. What is the process where a liquid changes into a gas?

Q3. When air holds the maximum possible moisture at a given temperature, it is called:

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

Frequently asked questions

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

According to the NCERT solutions, Oxygen is the most important constituent of the atmosphere for human beings due to its role in respiration.

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.

What are the main types of precipitation mentioned?

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

Why does water vapor decrease with altitude?

Water vapor decreases rapidly with altitude because both evaporation rates 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.

Content reviewed by the NCERT Help team. Editorial Team and update policy

NCERT Solutions PDF PDF on NCERT Help. URL unchanged for search indexing.