Class 7 Geography Chapter 6 Ratna Sagar

 Short Answer type questions:-

Q1. What are the main elements of weather and climate?

Ans. The main elements of weather and climate are-

        - Temperature of atmosphere

        - Atmospheric Pressure

        - Winds

        - Humidity 

        -  Precipitation

Q2. How is the atmosphere heated?

Ans. Insolation is absorbed by the earth surface and heat absorbed in day time is radiated back in the atmosphere, which is absorbed and maintained by greenhouse gasses near the surface of earth.

Q3. What do you mean by humidity in the atmosphere? How do we express it?

Ans. At a particular temperature the ratio of the moisture holding capacity and the actual amount of moisture present in atmosphere represents the level of humidity. 

Q4. Name the different forms of condensation and precipitation.

Ans. Different forms of condensation are- due, fog and clouds.

Long Answer type Questions:- 

Q1. Explain the factors responsible for the changes in atmospheric pressure on the earth's surface.

Ans. The factors responsible for the change in atmospheric pressure on the earth's surface are as follows:-

- Unequal heating of the earth- Different parts of the earth receives different level of insolation, which depends upon distance from the equator, when we move towards poles then the amount of radiation received by earth surface decreases in both hemisphere.

- Deflection of wind- due to earth rotation pressure belts are also affected and the earth is divided into seven pressure belts.

Q2. Describe the main features of planetary winds.

Ans. The main features of planetary winds are as follows:-

        - It blows in a particular direction throughout the year.

        - It is formed because of the presence of permanent high and low pressure belts on the surface of the earth.

Q3. How does the amount of moisture in the atmosphere vary from place to place and also from time to time?

Ans. The amount of moisture in the atmosphere vary from place to place and from time to time because-

    - The air in the equatorial region has more moisture than other regions of the world.

    - The air has more moisture during the summer than winter season.

    - The amount of moisture increases with increase in height above the sea level.

    - The amount of moisture is almost zero in the cold air of the polar region during the winter months.

Q4. Name and explain the various types of rainfall.

Ans. The various types of rainfall are as follows:-

        - Convectional Rainfall- Air gets heated after coming in contact with earth and becomes lighter. It rises up and become cooler with increase in height, which leads to condensation and formation of cumulus clouds, these clouds cause rainfall with thunder and lightning. Such type of rainfall is experienced every near the equator.

        - Orographic rainfall- When the moist air ascend along the slop of any mountain, then it leads to condensation and formation of clouds and cause rainfall. Such type of rainfall is experienced in areas near the mountains.

        - Cyclonic Rainfall- Cyclones are formed in warm sea, the air present here creates low pressure and cold wind blow towards these areas, when cold and warm wind comes in contact the lighter warm wind rides the cold wind, which increase the height of the warm air and condensation takes place in the warm air and rainfall takes place in along the path of cyclone.