In the context of the structure of the atmosphere, consider the following statements regarding the Troposphere: 1. The temperature in this layer increases with height. 2. Its thickness is greatest at the equator and least at the poles. 3. It is devoid of dust particles and water vapour. Which of the statements given above is/are correct?

The correct option is 2 only Explanation The Troposphere is the lowermost layer of the atmosphere. It is the most important layer for all biological activity and weather phenomena. The height of this layer varies significantly depending on latitude and season. Statement-wise Analysis - Statement 1 is Incorrect: The thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. Its height is approximately 18 km at the equator and roughly 8 km near the poles. - Statement 2 is Correct: In the troposphere, temperature decreases with an increase in height. This rate of decrease is known as the Normal Lapse Rate, which is approximately 6.5°C for every 1000 meters of ascent. The temperature increases with height in the Stratosphere and Thermosphere, not the Troposphere. - Statement 3 is Incorrect: The troposphere is not devoid of dust particles and water vapour. In fact, it contains the vast majority of the atmosphere's water vapour and aerosols (dust, pollen, etc.). Consequently, all weather changes-such as cloud formation, rainfall, and storms-occur exclusively in this layer. Key Takeaway The Troposphere is characterized by a decrease in temperature with altitude (Normal Lapse Rate), contains almost all atmospheric water vapour and dust, and exhibits variable thickness (highest at the equator, lowest at the poles).

NCERT Class 11 Geography — Chapter 1: Composition and Structure of Atmosphere

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In the context of the structure of the atmosphere, consider the following statements regarding the Troposphere:

The temperature in this layer increases with height.
Its thickness is greatest at the equator and least at the poles.
It is devoid of dust particles and water vapour.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 and 3 only
B1, 2 and 3
C1 only
D2 only

Did you get this right?

Solution

The correct option is

2 only

Explanation

The Troposphere is the lowermost layer of the atmosphere. It is the most important layer for all biological activity and weather phenomena. The height of this layer varies significantly depending on latitude and season.

Statement-wise Analysis

Statement 1 is Incorrect: The thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. Its height is approximately 18 km at the equator and roughly 8 km near the poles.
Statement 2 is Correct: In the troposphere, temperature decreases with an increase in height. This rate of decrease is known as the Normal Lapse Rate, which is approximately 6.5°C for every 1000 meters of ascent. The temperature increases with height in the Stratosphere and Thermosphere, not the Troposphere.
Statement 3 is Incorrect: The troposphere is not devoid of dust particles and water vapour. In fact, it contains the vast majority of the atmosphere's water vapour and aerosols (dust, pollen, etc.). Consequently, all weather changes-such as cloud formation, rainfall, and storms-occur exclusively in this layer.

Key Takeaway

The Troposphere is characterized by a decrease in temperature with altitude (Normal Lapse Rate), contains almost all atmospheric water vapour and dust, and exhibits variable thickness (highest at the equator, lowest at the poles).

Your note

More from Chapter 1: Composition and Structure of Atmosphere

Consider the following statements regarding the composition of the atmosphere: 1. The proportion of gases remains constant up to the highest layers of the atmosphere. 2. Nitrogen is the most abundant gas in the atmosphere. 3. Nitrogen and Oxygen make up the bulk of the atmosphere. Which of the statements given above is/are correct?

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Which of the following is the main reason for the rising volume of carbon dioxide in the atmosphere?

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Consider the following statements regarding water vapour in the atmosphere: 1. It is a variable gas that increases with altitude. 2. It accounts for less than one % of the air by volume in the dry and cold polar regions. 3. It absorbs parts of the insolation from the sun and preserves the earth’s radiated heat. Which of the statements given above is/are correct?

medium

With reference to the composition of the atmosphere, consider the following statements: 1. Oxygen is found in substantial quantities at heights above 120 km from the earth's surface. 2. Carbon dioxide is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation. 3. Carbon dioxide and water vapour are found in uniform concentration up to the exosphere. Which of the statements given above is/are correct?

medium

Which one of the following is the most likely reason for the higher concentration of dust particles in subtropical and temperate regions compared to equatorial regions?

easy

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The correct option is

2 only

Explanation

Statement-wise Analysis

Statement 1 is Incorrect: The thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. Its height is approximately 18 km at the equator and roughly 8 km near the poles.
Statement 2 is Correct: In the troposphere, temperature decreases with an increase in height. This rate of decrease is known as the Normal Lapse Rate, which is approximately 6.5°C for every 1000 meters of ascent. The temperature increases with height in the Stratosphere and Thermosphere, not the Troposphere.
Statement 3 is Incorrect: The troposphere is not devoid of dust particles and water vapour. In fact, it contains the vast majority of the atmosphere's water vapour and aerosols (dust, pollen, etc.). Consequently, all weather changes-such as cloud formation, rainfall, and storms-occur exclusively in this layer.