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Important questions on Atmospheric Pollution

What happens when higher energy ultraviolet radiations act on the oxygen at the higher level of the atmosphere?

View Answer

Ozone layer forms due to a combination of the molecular and elemental form of oxygen in the presence of UV rays. When high energy ultraviolet radiations act on the oxygen at the high level of atmosphere ozone is formed.

Freon gas causing stratospheric  depletion is mainly released from

A

Refrigerator

B

Automobile

C

Thermal power plant

D

Steel industry

View Answer

Freon or Aerosols or Chlorofluorocarbons (CFCs) are the chemicals used as refrigerants, propellants and solid plastic foams. The chemicals are also released as  aerosol by jets. Along with nitrous oxide, CFCs react with ozone of ozonosphere and deplete the same.
So, the correct answer is 'Refrigerator'

The result of ozone hole is

A

Acid rain

B

UV radiations reach the surface of earth

C

Global warming

D

Green house effect

View Answer

Ozone hole or thinning of ozone layer increases the amount of UV-B radiations reaching the earth. The increased ultraviolet radiations reaching the earth leads to increased incidence of cataract, skin cancers, herpes, dimming of eyesight, photo burning, snow blindness and deficient functioning of immune system. UV radiations also inhibit photosynthesis leading to decreased productivity.

What is the abundance of oxygen in the universe?

A

2nd most common element, by mass

B

3rd most common element, by mass

C

5th most abundant element, by mass

D

Oxygen is relatively rare in the universe

View Answer

Oxygen is the most abundant element in the universe and makes up nearly 21% of the earth's atmosphere. Oxygen accounts for nearly half of the mass of the earth's crust, two thirds of the mass of the human body and nine tenths of the mass of water.

The temperature in troposphere with altitude:

A

increases

B

decreases

C

increases and then decreases

D

decreases and then increases

View Answer

The temperature of the troposphere generally decreases as altitude increases. The rate at which the temperature decreases is called the environmental lapse rate (ELR). 

In which layer, most of the atmospheric air is present?

A

Troposphere

B

Stratosphere

C

Mesosphere

D

Thermosphere

View Answer

Fifty percent of the total mass of the atmosphere is located in the lower of the troposphere. Nearly all atmospheric water vapour or moisture is found in the troposphere. So, it is the layer where most of the earth's weather takes place.

Freon gas causing stratosphere depletion is mainly released from

A

Refrigerators

B

Automobiles

C

Thermal power plants

D

Steel industry

View Answer

Freon gas is a type of chlorofluorocarbon (CFC) i.e., it contains carbon and hydrogen along with fluorine and chlorine. It is used as a refrigerant. CFCs release chlorine atoms in the atmosphere that react with ozone and cause its depletion. Hence, Freon causes ozone depletion and it is released from refrigerators.
So, the correct answer is 'Refrigerators'.

The layer of air around the earth is known as __________.

View Answer

The layer of air around the earth is known as atmosphere.

Ozone is present as a chief constituent in which region of the atmosphere?

A

Troposphere

B

Stratosphere

C

Mesosphere

D

Thermosphere

View Answer

The stratosphere is a second layer of Earth's atmosphere. The troposphere, the lowest layer, is right below the stratosphere. The next higher layer above the stratosphere is the mesosphere.
Ozone is a three oxygen molecule that are abundant in the stratosphere, it absorbs energy from incoming ultraviolet radiation from the Sun. 

The region in atmosphere containing water vapour is:

A

thermosphere

B

stratosphere

C

troposphere

D

mesosphere

View Answer

The troposphere is the lowest region of the atmosphere, i;e., closest to earth's surface. It extends roughly to a height of about 11 km. This is the region of all living organisms including, animals and plants. 

About 70% of the total mass of the atmosphere and practically all the water vapours and dust particles are concentrated in this region

Hence, the correct option is

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