Question 1

Q1: (i) Which one of the following is the most important constituent of the atmosphere for human beings? (a) Water vapour (b) Nitrogen (c) Dust particle (...

Accepted Answer

(d) Oxygen Explanation: While water vapour is crucial for weather phenomena as discussed in the chapter, oxygen is the most important constituent of the atmosphere for the survival of human beings as it is essential for respiration.

Question 2

Q2: (ii) Which one of the following process is responsible for transforming liquid into vapour? (a) Condensation (b) Transpiration (c) Evaporation (d) Pre...

Accepted Answer

(c) Evaporation Explanation: The chapter states, "Evaporation is a process by which water is transformed from liquid to gaseous state."

Question 3

Q3: (iii) The air that contains moisture to its full capacity : (a) Relative humidity (b) Specific humidity (c) Absolute humidity (d) Saturated air

Accepted Answer

(d) Saturated air Explanation: According to the text, "The air containing moisture to its full capacity at a given temperature is said to be saturated."

Question 4

Q4: (iv) Which one of the following is the highest cloud in the sky? (a) Cirrus (b) Stratus (c) Nimbus (d) Cumulus

Accepted Answer

(a) Cirrus Explanation: The text specifies that "Cirrus clouds are formed at high altitudes (8,000 - 12,000 m)," which is the highest altitude range mentioned for any cloud type.

Question 5

Q1: (i) Name the three types of precipitation.

Accepted Answer

The three main types of precipitation are:    Rainfall: Precipitation in the form of liquid water droplets.    Snowfall: Precipitation in the form of fine flakes of snow, which are hexagonal ice crystals. *   Sleet and Hail: Sleet consists of frozen raindrops, while hail is composed of small, rounde...

Question 6

Q2: (ii) Explain relative humidity.

Accepted Answer

Relative humidity is the percentage of moisture present in the air compared to the maximum amount of moisture the air can hold at a specific temperature. It is affected by changes in air temperature; as temperature increases, the air's capacity to hold moisture also increases, which can lower the re...

Question 7

Q3: (iii) Why does the amount of water vapour decreases rapidly with altitude?

Accepted Answer

The amount of water vapour decreases with altitude primarily because it is derived from evaporation and transpiration at the Earth's surface. Additionally, as altitude increases, the temperature of the air decreases. Colder air has a lower capacity to hold water vapour, causing the moisture content...

Question 8

Q4: (iv) How are clouds formed? Classify them.

Accepted Answer

Clouds are formed by the condensation of water vapour in the free air at considerable heights. This condensation occurs around tiny particles like dust and salt, known as hygroscopic nuclei, when moist air cools to its dew point. Clouds are classified into four main types based on height and appeara...

Question 9

Q1: (i) Discuss the salient features of the world distribution of precipitation.

Accepted Answer

The distribution of precipitation across the world is uneven and influenced by several factors. The salient features are as follows:    General Trend: In general, rainfall decreases as one moves from the equator towards the poles.    Land and Water Bodies: Coastal areas receive more rainfall than th...

Question 10

Q2: (ii) What are forms of condensation? Describe the process of dew and frost formation.

Accepted Answer

Condensation is the transformation of water vapour into water. The forms of condensation depend on temperature and location. The main forms are dew, frost, fog, and clouds. Dew Formation: Dew consists of water droplets that form when moisture from the air is deposited on cooler solid surfaces like s...

NCERT Solutions