Consider the following statements regarding the Exosphere: 1. It is the uppermost layer of the atmosphere. 2. It contains very dense air to support satellites. 3. Heavy gases like nitrogen and oxygen are concentrated in this layer. Which of the statements given above is/are correct?

The correct option is (a). Explanation The Earth's atmosphere is divided into five distinct layers based on thermal properties and composition. The exosphere represents the transitional zone between the Earth's atmosphere and the vacuum of outer space. - Statement 1 is Correct: The exosphere is the uppermost layer of the atmosphere. It lies above the thermosphere and extends from approximately 600 km altitude up to 10,000 km, where it gradually merges with interplanetary space. - Statement 2 is Incorrect: The air in the exosphere is extremely rarefied (thin), possessing very low density. It does not contain dense air; rather, the density is so low that particles travel hundreds of kilometers without colliding. Satellites orbit in this layer specifically because the friction (atmospheric drag) is negligible, not because the air supports them. - Statement 3 is Incorrect: Heavy gases such as nitrogen and oxygen are concentrated in the lower layers of the atmosphere (Troposphere and Stratosphere) due to gravity. The exosphere contains light gases like helium and hydrogen, which float into space from this layer. Key Takeaway: The exosphere is the outermost atmospheric layer characterized by extremely low air density and the presence of light gases like hydrogen and helium, distinct from the heavy gas concentration found in the lower atmosphere.

NCERT Class 7 Geography — Chapter 1: Air

mcqmedium

Consider the following statements regarding the Exosphere:

It is the uppermost layer of the atmosphere.
It contains very dense air to support satellites.
Heavy gases like nitrogen and oxygen are concentrated in this layer.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (a).

Explanation

The Earth's atmosphere is divided into five distinct layers based on thermal properties and composition. The exosphere represents the transitional zone between the Earth's atmosphere and the vacuum of outer space.

Statement 1 is Correct: The exosphere is the uppermost layer of the atmosphere. It lies above the thermosphere and extends from approximately 600 km altitude up to 10,000 km, where it gradually merges with interplanetary space.
Statement 2 is Incorrect: The air in the exosphere is extremely rarefied (thin), possessing very low density. It does not contain dense air; rather, the density is so low that particles travel hundreds of kilometers without colliding. Satellites orbit in this layer specifically because the friction (atmospheric drag) is negligible, not because the air supports them.
Statement 3 is Incorrect: Heavy gases such as nitrogen and oxygen are concentrated in the lower layers of the atmosphere (Troposphere and Stratosphere) due to gravity. The exosphere contains light gases like helium and hydrogen, which float into space from this layer.

Key Takeaway: The exosphere is the outermost atmospheric layer characterized by extremely low air density and the presence of light gases like hydrogen and helium, distinct from the heavy gas concentration found in the lower atmosphere.

Your note

More from Chapter 1: Air

With reference to the composition of the atmosphere, consider the following statements: 1. Nitrogen is the most plentiful gas in the air. 2. Carbon dioxide and argon together make up the bulk of the atmosphere. 3. Helium and hydrogen are present in the atmosphere in lesser quantities than nitrogen. Which of the statements given above is/are correct?

easy

Which of the following gases is primarily responsible for the "greenhouse effect" by trapping the heat radiated from the earth?

easy

Consider the following statements regarding the circulation of air: 1. When air is heated, it contracts and becomes heavier. 2. Cold air is denser and tends to sink down. 3. Air circulation occurs when cold air from surrounding areas rushes to fill the gap left by rising hot air. Which of the statements given above is/are correct?

medium

With reference to the nitrogen cycle in the atmosphere, consider the following statements: 1. Plants absorb nitrogen directly from the air through their leaves. 2. Bacteria living in the soil and roots of some plants change the form of nitrogen for plant use. 3. Humans absorb all the nitrogen they inhale during breathing. Which of the statements given above is/are correct?

medium

Which one of the following best explains why the balance of carbon dioxide in the atmosphere is getting disturbed?

easy

Keep practising Chapter 1: Air

Work through every question from this NCERT chapter.

Browse all NCERT Class 7 Geography chapters

The correct option is (a).

Explanation

Statement 1 is Correct: The exosphere is the uppermost layer of the atmosphere. It lies above the thermosphere and extends from approximately 600 km altitude up to 10,000 km, where it gradually merges with interplanetary space.
Statement 2 is Incorrect: The air in the exosphere is extremely rarefied (thin), possessing very low density. It does not contain dense air; rather, the density is so low that particles travel hundreds of kilometers without colliding. Satellites orbit in this layer specifically because the friction (atmospheric drag) is negligible, not because the air supports them.
Statement 3 is Incorrect: Heavy gases such as nitrogen and oxygen are concentrated in the lower layers of the atmosphere (Troposphere and Stratosphere) due to gravity. The exosphere contains light gases like helium and hydrogen, which float into space from this layer.