Question 1

Q1: (i) Which one of the following gases constitutes the major portion of the atmosphere? (a) Oxygen (b) Nitrogen (c) Argon (d) Carbon dioxide

Accepted Answer

(b) Nitrogen Nitrogen is the most abundant gas, making up the major portion of the atmosphere's composition.

Question 2

Q1: (i) Which one of the following gases constitutes the major portion of the atmosphere? (a) Oxygen (b) Nitrogen (c) Argon (d) Carbon dioxide

Accepted Answer

(b) Nitrogen is the correct answer. While the provided text focuses on the meteorological importance of gases like oxygen and carbon dioxide, nitrogen is the most abundant gas, constituting the major portion of the atmosphere.

Question 3

Q2: (ii) Atmospheric layer important for human beings is: (a) Stratosphere (b) Mesosphere (c) Troposphere (d) Ionosphere

Accepted Answer

(c) Troposphere is the correct answer. The text states that the troposphere is the most important layer for all biological activity, as it contains the air we breathe, water vapour, and is where all weather phenomena occur.

Question 4

Q2: (ii) Atmospheric layer important for human beings is: (a) Stratosphere (b) Mesosphere (c) Troposphere (d) Ionosphere

Accepted Answer

(c) Troposphere The troposphere is the most important layer for all biological activity. It contains the air we breathe, and all weather and climate changes that affect life on Earth occur in this layer.

Question 5

Q3: (iii) Sea salt, pollen, ash, smoke soot, fine soil - these are associated with: (a) Gases (b) Dust particles (c) Water vapour (d) Meteors

Accepted Answer

(b) Dust particles These are all examples of small solid particles found in the atmosphere, which originate from various sources like sea salts, fine soil, smoke-soot, ash, and pollen.

Question 6

Q3: (iii) Sea salt, pollen, ash, smoke soot, fine soil - these are associated with: (a) Gases (b) Dust particles (c) Water vapour (d) Meteors

Accepted Answer

(b) Dust particles is the correct answer. The chapter explicitly lists these items as examples of small solid particles that the atmosphere holds, originating from various sources like sea salts, fine soil, smoke-soot, ash, and pollen.

Question 7

Q4: (iv) Oxygen gas is in negligible quantity at the height of atmosphere: (a) 90 km (b) 120 km (c) 100 km (d) 150 km

Accepted Answer

(b) 120 km According to the chapter, the proportion of gases changes in the higher layers of the atmosphere, and oxygen becomes almost negligible at a height of 120 km.

Question 8

Q4: (iv) Oxygen gas is in negligible quantity at the height of atmosphere: (a) 90 km (b) 120 km (c) 100 km (d) 150 km

Accepted Answer

(b) 120 km is the correct answer. The text clearly mentions under the 'Composition of the Atmosphere' section that "oxygen will be almost in negligible quantity at the height of 120 km."

Question 9

Q5: (v) Which one of the following gases is transparent to incoming solar radiation and opaque to outgoing terrestrial radiation? (a) Oxygen (b) Nitrogen...

Accepted Answer

(d) Carbon dioxide is the correct answer. The chapter states that carbon dioxide is meteorologically very important because it is "transparent to the incoming solar radiation but opaque to the outgoing terrestrial radiation," which is the primary mechanism of the greenhouse effect.

Question 10

Q5: (v) Which one of the following gases is transparent to incoming solar radiation and opaque to outgoing terrestrial radiation? (a) Oxygen (b) Nitrogen...

Accepted Answer

(d) Carbon dioxide Carbon dioxide is a meteorologically important gas because it allows incoming solar radiation to pass through but absorbs the outgoing terrestrial radiation, contributing to the greenhouse effect.

Question 11

Q1: (i) What do you understand by atmosphere?

Accepted Answer

The atmosphere is a mixture of different gases that envelopes the Earth. It is an integral part of the Earth's mass and contains life-giving gases like oxygen for animals and carbon dioxide for plants. 99 per cent of its total mass is confined to a height of 32 km from the Earth's surface.

Question 12

Q1: (i) What do you understand by atmosphere?

Accepted Answer

The atmosphere is a mixture of different gases that envelops the Earth. It is an integral part of the Earth's mass and contains life-sustaining gases like oxygen for animals and carbon dioxide for plants. Ninety-nine percent of its total mass is confined to a height of 32 km from the Earth's surface...

Question 13

Q2: (ii) What are the elements of weather and climate?

Accepted Answer

The main elements of weather and climate are the atmospheric conditions that are subject to change and influence human life. These elements, as listed in the chapter, are temperature, pressure, winds, humidity, clouds, and precipitation.

Question 14

Q2: (ii) What are the elements of weather and climate?

Accepted Answer

The main elements of weather and climate are the atmospheric conditions that are subject to change and influence human life. These elements include temperature, pressure, winds, humidity, clouds, and precipitation.

Question 15

Q3: (iii) Describe the composition of atmosphere.

Accepted Answer

The atmosphere is composed of three main components: gases, water vapour, and dust particles. Gases like carbon dioxide and ozone play crucial roles. Water vapour is a variable gas that absorbs heat, and dust particles act as nuclei for condensation to form clouds.

Question 16

Q3: (iii) Describe the composition of atmosphere.

Accepted Answer

The atmosphere is primarily composed of three main components: gases, water vapour, and dust particles. Gases like oxygen and carbon dioxide are vital for life. Water vapour is a variable gas that absorbs heat and contributes to atmospheric stability. Dust particles act as nuclei for condensation to...

Question 17

Q4: (iv) Why is troposphere the most important of all the layers of the atmosphere?

Accepted Answer

The troposphere is the most important atmospheric layer because it contains the air essential for life and all biological activities occur here. Furthermore, all changes in climate and weather, such as the formation of clouds and rain, take place within this layer.

Question 18

Q4: (iv) Why is troposphere the most important of all the layers of the atmosphere?

Accepted Answer

The troposphere is the most important layer for all biological activity because it contains the air we breathe, along with dust particles and water vapour. Furthermore, all changes in climate and weather, which directly impact life on Earth, take place within this lowermost layer of the atmosphere.

Question 19

Q1: (i) Describe the composition of the atmosphere.

Accepted Answer

The atmosphere is composed of a mixture of gases, water vapour, and dust particles. The proportions of these components vary with altitude and location.    Gases: The atmosphere contains several gases. Carbon dioxide is meteorologically significant as it is transparent to incoming solar radiation bu...

Question 20

Q1: (i) Describe the composition of the atmosphere.

Accepted Answer

The atmosphere is a mixture of various gases, water vapour, and dust particles. The composition of the atmosphere is as follows:    Gases: The atmosphere is composed of several gases. Carbon dioxide is a meteorologically significant gas as it is transparent to incoming solar radiation but opaque to...

NCERT Solutions