Consider the following statements regarding the atmosphere: 1. It is a thin layer of air that surrounds the earth. 2. It extends only up to 10 km above the surface of the earth. 3. The air becomes denser as we move higher in the atmosphere. Which of the statements given above is/are correct?

The correct option is (a). Explanation The atmosphere is a gaseous envelope surrounding the Earth, held in place by the planet's gravitational pull. It is a crucial component of the environment that supports life by providing essential gases, regulating temperature, and shielding the surface from harmful solar radiation. Statement-wise Analysis: - Statement 1 is Correct: The atmosphere is described as a thin layer of air that surrounds the Earth. While it extends upwards for hundreds of kilometers, relative to the Earth's radius (approximately 6,371 km), it is a very thin protective layer. - Statement 2 is Incorrect: The atmosphere extends far beyond 10 km. While the troposphere (the lowest layer) extends roughly up to 10–18 km depending on latitude, the entire atmosphere extends up to about 1,600 km above the surface. However, 99% of the total mass of the atmosphere is confined to the height of 32 km from the earth's surface. - Statement 3 is Incorrect: The density of the atmosphere is not uniform. It is maximum at the sea level and decreases rapidly as we move up. Gravity pulls gas molecules toward the surface, compressing the air at lower altitudes, making it denser than the air at higher altitudes. Key Takeaway: The atmosphere is a vast gaseous layer extending hundreds of kilometers above the surface, characterized by a decrease in density and pressure with increasing altitude.

NCERT Class 6 Environment & Ecology — Chapter 2: Air around us

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Consider the following statements regarding the atmosphere:

It is a thin layer of air that surrounds the earth.
It extends only up to 10 km above the surface of the earth.
The air becomes denser as we move higher in the atmosphere.

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 atmosphere is a gaseous envelope surrounding the Earth, held in place by the planet's gravitational pull. It is a crucial component of the environment that supports life by providing essential gases, regulating temperature, and shielding the surface from harmful solar radiation.

Statement-wise Analysis:

Statement 1 is Correct: The atmosphere is described as a thin layer of air that surrounds the Earth. While it extends upwards for hundreds of kilometers, relative to the Earth's radius (approximately 6,371 km), it is a very thin protective layer.
Statement 2 is Incorrect: The atmosphere extends far beyond 10 km. While the troposphere (the lowest layer) extends roughly up to 10–18 km depending on latitude, the entire atmosphere extends up to about 1,600 km above the surface. However, 99% of the total mass of the atmosphere is confined to the height of 32 km from the earth's surface.
Statement 3 is Incorrect: The density of the atmosphere is not uniform. It is maximum at the sea level and decreases rapidly as we move up. Gravity pulls gas molecules toward the surface, compressing the air at lower altitudes, making it denser than the air at higher altitudes.

Key Takeaway:

The atmosphere is a vast gaseous layer extending hundreds of kilometers above the surface, characterized by a decrease in density and pressure with increasing altitude.

Your note

More from Chapter 2: Air around us

With reference to the composition of air, consider the following statements: 1. Nitrogen and oxygen together make up approximately 99% of the air. 2. Carbon dioxide constitutes the majority of the remaining 1% of air. 3. The composition of air varies from place to place. Which of the statements given above is/are correct?

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Consider the following statements regarding water vapour in the air: 1. Air contains water vapour only during the rainy season. 2. When air comes in contact with a cool surface, water vapour condenses. 3. The presence of water vapour in air is essential for the water cycle in nature. Which of the statements given above is/are correct?

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With reference to the burning of fuel and its by-products, consider the following statements: 1. Burning can occur in the absence of oxygen if nitrogen is present. 2. Burning of fuel produces smoke which contains a few gases and fine dust particles. 3. Smoke produced by burning fuel is generally beneficial to respiratory health. Which of the statements given above is/are correct?

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Consider the following statements regarding the "dust particles" in the air: 1. Dust particles are always present in the air. 2. The presence of dust particles in air is constant irrespective of time and place. 3. Breathing through the mouth can allow harmful dust particles to enter the body. Which of the statements given above is/are correct?

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The correct option is (a).

Explanation

Statement-wise Analysis:

Statement 1 is Correct: The atmosphere is described as a thin layer of air that surrounds the Earth. While it extends upwards for hundreds of kilometers, relative to the Earth's radius (approximately 6,371 km), it is a very thin protective layer.
Statement 2 is Incorrect: The atmosphere extends far beyond 10 km. While the troposphere (the lowest layer) extends roughly up to 10–18 km depending on latitude, the entire atmosphere extends up to about 1,600 km above the surface. However, 99% of the total mass of the atmosphere is confined to the height of 32 km from the earth's surface.
Statement 3 is Incorrect: The density of the atmosphere is not uniform. It is maximum at the sea level and decreases rapidly as we move up. Gravity pulls gas molecules toward the surface, compressing the air at lower altitudes, making it denser than the air at higher altitudes.

Key Takeaway:

The atmosphere is a vast gaseous layer extending hundreds of kilometers above the surface, characterized by a decrease in density and pressure with increasing altitude.