LONG ANS. QUESTIONS(5 Mark)

Question 15 Marks

Examine the structure of the atmosphere.

Answer

The structure of atmosphere is divided into five layers. These include:-

Troposphere:- Its average height is 13km and all weather phenomena like rainfall, fog and hailstorm occur here. The air we breathe is found here.
Stratosphere:- It extends up to a height of 50km. It is free from weather conditions and clouds making it ideal for flying aeroplanes. It even contains ozone layer, which protects us from the harmful sun rays.
Mesosphere:- It extends up to a height of 80km. Meteorites burn up in this layer on entering from the space.
Thermosphere:- In this, the temperature rises with increasing height. Ionosphere is a part of this layer. It extends 80-400km. It even helps in radio transmission. Radio waves transmitted from the earth are reflected back to the earth by this layer.
Exosphere:- It is the upper most layer and has very thin air. Light gases like helium and hydrogen float into the space from here.

Question 25 Marks

How are winds classified?

Answer

Winds are classified into three types:-

Permanent winds:- It consists of trade winds, westerlies and easterlies. These blow constantly throughout the year in a particular direction.
Seasonal winds:- These winds change their direction in different seasons, like monsoons in India.
Local winds:- These blow only during a particular part of the day or year in one area or the whole area; for examples, land and sea breeze or winds in North India.

Question 35 Marks

Write a short note on different layers of atmosphere.

Answer

Our atmosphere is divided into five layers starting from the earth’s surface.

Troposphere: This layer is the most important layer of the atmosphere. Its average height is 13km. The air we breathe exists here. Almost all the weather phenomena like rainfall, fog and hailstorm occur in this layer.
Stratosphere: Above the troposphere lies the stratosphere. It extends up to a height of 50km. This layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying aeroplanes. One important feature of stratosphere is that it contains a layer of ozone gas which protects us from the harmful effect of the sun rays.
Mesosphere: This is the third layer of the atmosphere. It lies above the stratosphere. It extends up to the height of 80km. Meteorites burn up in this layer on entering from the space.
Thermosphere: In thermosphere temperature rises very rapidly with increasing height. Ionosphere is a part of this layer. It extends between 80-400km. This layer helps in radio transmission. In fact, radio waves transmitted from the earth are reflected back to the earth by this layer.
Exosphere: The upper most layer of the atmosphere is known as exosphere. This layer has very thin air. Light gases like helium and hydrogen float into the space from here.

Question 45 Marks

How does insolation affect temperature?

Answer

The amount of insolation decreases from the equator towards the poles.
Therefore, the temperature decreases in the same manner.
If the earth’s temperature rises too high, it would become too warm for some crops to grow.
Temperature in cities is much higher than that of villages.
The concrete and metals in buildings and the asaphalt of roads get heated up during the day.
This heat is released during the night.
Further, the crowded high-rise buildings of the cities trap the warm air and thus raise the temperature of the cities.

Question 55 Marks

Match the contents of Column A with that of Column B

S.No.	Column A		Column B
1.	Temperature	(a)	Bacteria in soil
2.	Pressure	(b)	Thermosphere
3.	Seasonal wind	(c)	Barometer
4.	Radio waves transmission	(d)	Thermometer
5.	Nitrogen from air	(e)	Change directions in different seasons

Answer

S.No.	Column A		Column B
1.	Temperature	(d)	Thermometer
2.	Pressure	(c)	Barometer
3.	Seasonal wind	(e)	Change directions in different seasons
4.	Radio waves transmission	(b)	Thermosphere
5.	Nitrogen from air	(a)	Bacteria in soil

Question 65 Marks

Give an account of the different layers of the atmosphere.

Answer

Our atmosphere has five different layers. They are:

Troposphere: This is the most important layer of the atmosphere with average height of 13km from the earth. It is in this layer that we find the air that we breathe. Almost all the weather phenomena such as rainfall, fog and hailstorm occur here.
Stratosphere: This layer extends up to a height of 50km. It presents the most ideal conditions for flying aeroplanes. It contains a layer of ozone gas which protects us from the harmful effect of the sunrays.
Mesosphere: This layer extends up to the height of 80km. Meteorites bum up in this layer on entering from the space.
Thermosphere: In this layer temperature rises very rapidly with increasing height. Ionosphere is a part of this layer. It extends between 80-400km. This layer helps in radio transmission. Radio waves transmitted from the earth are reflected back to the earth by this layer.
Exosphere: It is the uppermost layer where there is very thin air. Light gases such as helium and hydrogen float into the space from here.

Question 75 Marks

How does air pressure get affected due to layers of atmosphere?

Answer

The pressure falls rapidly as we go up the layers of the atmosphere.
The air pressure is highest at the sea level and decreases with height.
Horizontally, the distribution of air pressure is influenced by temperature of air at a given place.
In areas where temperature is high, the air gets heated and thus rises.
This creates a low-pressure area, which leads to cloudy skies and wet weather.
In areas with low temperature, air is cold and pressure is heavy.
Heavy air sinks and creates a high-pressure area.
High pressure is associated with clear and sunny skies.
Air moves from high-pressure to low pressure areas.

Question 85 Marks

Describe the fury of cyclone taking example of 'Super cyclone' of Odisha.

Answer

Odisha on eastern sea coast of India is prone to cyclones originating in Bay of Bengal.

Odisha was hit by cyclone on 17th-18th October 1999 and again on 29th October.
Cyclone originated as a 'depression' in the Gulf of Thailand near Port Blair.
It moved in northwest direction on 25th October and intensified into super cyclone and hit Odisha.
Wind speed was upto 260km/ hr which lasted for 36 hours.
Trees were uprooted kutcha houses, roof tops industrial sheds etc blown away.
Power supply and communication lines damaged.
Continues rains flooded the major rivers. Tidal waves swept 20km of inland areas including cities of Bhubaneshwar and Cuttack and destructed 28 coastal towns.
7-10 m high tidal waves caused damage to paddy crops, vegetables fruits and agricultural land turned infertile due to salination.
13 million people were affected. Livestock was killed.
Plantations of teak, sal, bamboo, mangrove forests of Paradeep and Konark disappeared.

Social Science LONG ANS. QUESTIONS(5 Mark)