CLASS 7 CHAPTER-4 AIR AROUND US

GEOGRAPHY

CHAPTER-4

AIR AROUND US

QUESTION WITH ANSWER

( D) ANSWER THE FOLLOWING QUESTION IN BRIEF----

1. Name the layers of the atmosphere.

Answer-Troposphere, Stratosphere, Mesosphere and Thermosphere are the layers of the atmosphere.

2.How do absorb nitrogen through the soil.

Answer- Plants absorb nitrogen through the soil.

3.What is the importance of water vapours in the atmosphere?

Answer-Water  vapours in the atmosphere causes rainfall.

4.Name the different variables of atmosphere?

Answer-The different variables of atmosphere is temperature pressure of humidity.

5.What type of climate does Indian have?

Answer- India has Monsoonal climate.

(E) ANSWER THE FOLLOWING QUESTIONS.

1.What is the importance of carbon dioxide and oxygen for living beings?

Answer-

Importance of oxygen

1.All human beings or animals inhale oxygen form air to stay alive.

2. It is known as life supporting gas.

Importance of carbon dioxide

1. The trees utilize carbon dioxide during the process of photosynthesis.

2. Carbon dioxide absorbs heat of sun and warms up the lower atmosphere of the Earth's surface.

2.Name three major sources of pollutants in the air. Also state the ill-effects of these air pollutants.

Answer-

The major sources of air pollutants are as follow-

1.Automobiles in cities releases pollutants like carbon dioxide, lead particles etc.

2.Volconic eruption also add pollutants in air.

3.Forest fire also causes air pollution.

Air pollutants causing serious health problems like irritation in eyes, skin disease, respiratory diseases etc.

3.What is the importance of ozone gas? Why is global warming a threat to life on the earth?

Answer-

Ozone layer is very important as it acts as a filter and absorbs harmful ultra violet sun rays from reaching the earth's surface. This layer acts as a shield over the earth's surface.

The carbon dioxide has a property to absorbs heat, increases temperature of the atmosphere, which in turn increase the temperature over the earth surface. This is global warming. Global warming a threat to life on the earth.

4. How is rainfall caused? Explain it with the help of a diagram.

Answer-

As the hot air rises it reaches high in the atmosphere where it cools down due to the presence of low temperature there. The water present in the form of water vapours condenses into tiny droplets of water these tiny particles join together and form clouds. Due to the further cooling, these tiny condensed droplets these droplets became so heavy that the air cannot hold them. Hence they fall down as rainfall or snowfall.

  

5.Write the difference between weather and climate.

Answer-

Weather-

1.Weather refers to the state of atmosphere that includes in temperature pressure and humidity for specific place.

2. Weather may be change.

Climate-

1. Climate refers to the state of atmospheric condition that includes temperature rainfall pressure over long pointed of time.

2. But climate cannot be change.