# Class 8 Geography Chapter 3 Humidity and Clouds Answers

Maharashtra Board Class 8 Geography Solutions Chapter 3 Humidity and Clouds

Balbharti Maharashtra State Board Class 8 Geography Solutions Chapter 3 Humidity and Clouds Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Geography Solutions Chapter 3 Humidity and Clouds

Class 8 Geography Chapter 3 Humidity and Clouds Textbook Questions and Answers

## Exercises

1. Match the column and complete the chain:

 ‘A’ Column ‘B’ Column ‘C’ Column 1. Cirrus i. Vertical extent in the sky a. Roaring clouds 2. Cumulonimbus ii. Higher altitude b. Floating clouds 3. Nimbostratus iii. Medium altitude c. Continuous rainfall 4. Alto-cumulus iv Low altitude d. Snowflake clouds

 ‘A’ Column ‘B’ Column ‘C’ Column 1. Cirrus ii. Higher altitude d. Snowflake clouds 2. Cumulonimbus i. Vertical extent in the sky a. Roaring clouds 3. Nimbostratus iv Low altitude c. Continuous rainfall 4. Alto-cumulus iii. Medium altitude b. Floating clouds

2. Choose the correct word from the brackets and complete the sentences:
(Options: Cumulonimbus, relative humidity, absolute humidity, condensation, vapor-holding capacity)

(a) The ………….. of the air is dependent on the temperature of the air.

(b) The amount of vapour in 1 cu.m, of air shows the ………….

(c) As …………. is less in the desert areas, the air is dry there.

(d) ……………. type of clouds are indicators of the storm.

(e) In a free environment, the ………….. of the vapour present in the atmosphere takes place around the dust particles.

Q 3. Differentiate between: (a) Humidity and clouds

 Humidity Clouds 1. The proportion of water vapour in the air is called its humidity. 1. The process of changing of water vapour in the air into water is called condensation or densification. Clouds are forms of condensation at high elevation. 2. Humidity are of two types: Absolute Humidity and Relative Humidity 2. Clouds are divided into different types such as Cirrus, Alto-Stratus, Cumulus, etc. 3. Humidity is invisible. 3. Clouds are visible.

(b) Relative humidity and Absolute humidity (c) Cumulus clouds and cumulonimbus clouds

 Relative Humidity Absolute Humidity 1. The amount of water vapour present in air can be expressed as a percentage of the amount needed for saturation at the same temperature and the same volume. 1. The amount of water vapour in 1 cu.m. of air is the absolute humidity of the air. 2. It is expressed in percentage. 2. It is expressed in grams or kilograms per cubic meter. 3. Generally, relative humidity is more in the mornings and nights. In the afternoon, as temperature increases, relative humidity decreases. Near coastal areas, the relative humidity is more and so the air is moist. In desert areas, relative humidity is less. 3. The absolute humidity of the air near coastal areas is higher than air in the interior. Absolute humidity is higher in the equatorial areas while it reduces as we move towards the poles. The distribution of land and water on earth and the seasons also affect absolute humidity.

c. Cumulus clouds and Cumulonimbus clouds

 Cumulus clouds Cumulonimbus clouds 1. These clouds are formed extensively from 500 m to 6000 m altitude. 1. These are characteristic clouds which are indicators of thunderstorm. These look like huge mountains. 2. These are huge and dome-shaped. They are grey in colour. 2. These are dense and dark in colour. 3. The vertical expanse of these clouds increases so much that they turn into cumulonimbus clouds and bring rain 3. There is thunder accompanied by lightening. They bring rain with storm and may sometime bring hailstones.

(a) Why is the air in a region dry?
Answer: When there is less moisture in the air, the air in that region is dry. E.g. Rajasthan lies in a region with dry and hot air. There is hardly any moisture in the air.

(b) How is humidity measured?

Answer: Generally, humidity of the air is measured in grams per cubic meter. When the humidity in the air is 0 gm/cu.m., the air is said to be dry. If the humidity in the air at 30° C temperature is 37 gms/ cu.m. , then the air is said to be saturated.

ABSOLUTE HUMIDITY: The amount of water vapour in 1 cu.m. of air is the absolute humidity of the air.

RELATIVE HUMIDITY: The amount of water vapour present in air can be expressed as a percentage of the amount needed for saturation at the same temperature and same volume. It is expressed in percentage.

Relative humidity (R.H.) (%) =

(c) What are the prerequisites for condensation?

Answer: Temperature at dewpoint and high relative humidity are the perquisites for condensation.

(d) What is a cloud? Write its types.

Answer: Because of condensation, fine particles of ice and water float in the air at a greater height. They accumulate around dust particles in the air and become larger in size. Their accumulation together is called a cloud.

The following are the types of clouds:

1. High clouds: Clouds at an altitude of 7000 m to 14000 m are considered as high clouds. Cirrus, Cirro-Stratus and CirroCumulus are high clouds.
2. Medium clouds: Clouds at an altitude of 2000 m to 7000 m are considered as medium clouds. Alto-Stratus and Alto Cumulus are medium clouds.
3. Low clouds: Clouds at an altitude of less than 2000m are considered as low clouds. Strato-Cumulus, Stratus, Nimbostratus, Cumulus and Cumulonimbus are low clouds

(e) Which type of clouds give rain?

Answer: Nimbostratus and cumulonimbus type of clouds give rain.

(f) On what does the percentage of relative humidity depend?

Answer: Relative humidity (R.H.) (%) =

The percentage of relative humidity depends on the absolute humidity and vapour-holding capacity of the air at a given temperature.

Q 5. Give geographical reasons:

(a) Clouds float in the sky.

Answer: Because of condensation, fine particles of ice and water float in the air at a greater height. They accumulate around dust particles in the air and become larger in size. Their accumulation together is called a cloud. Because of vertical flow of the wind, they float in the atmosphere.

(b) The proportion of relative humidity changes according to altitude.

1. The temperature is found to be comparatively high in the areas at sea level. Due to high temperature, moisture-holding capacity of air near sea level is found to be high. Therefore, the humidity of the air at sea level is comparatively high.

2. The temperature is found to be comparatively low in the areas at high altitude. Due to low temperature, moisture-holding capacity of air at high altitudes is found to below. Therefore, the humidity of the air at high altitude is comparatively low. In this way, the proportion of relative humidity changes according to the altitude.

(c) Air becomes saturated.

Answer: At a certain temperature, the moisture holding capacity of air becomes equal to the proportion of moisture present in it. No more moisture can be absorbed by the air. Thus, air becomes saturated.

(d) Cumulus clouds change into cumulonimbus clouds

Answer: Cumulus clouds are formed extensively from 500 m to 6000 m altitude. The vertical flow of the air adds to the formation of these clouds. These are huge and dome-shaped. They are grey in colour. Cumulus clouds are an indicator of pleasant weather. The vertical expanse of these clouds increases so much that they turn into cumulonimbus clouds and bring rain.

Q 6. Solve the following:

(a) When the temperature of the air is 30° C, its vapour-holding capacity is 30.37 gms/ cu.m. If absolute humidity is 18 gms / cu.m. then what would be the relative humidity?

= 59.26 %

(b) What would be the absolute humidity of air if 1 cu.m. air contains 4.08 gms of vapour at 0°C temperature? .

Q 7. Collect the weather related information from newspapers for the month of July.

Relate the difference in the maximum and minimum temperatures with humidity.

Answer: Students should do this activity on their own.

ACTIVITY :

Make a table showing the types of clouds. Use various photographs.