CBSE Class 8 Science - Pollution of Air and Water (1)
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Q.1.Choose the correct answer:
a-Which gas is found in largest percentage in air?
i-Oxygen ii-Nitrogen iii-Carbon dioxide iv-Helium
b-What is the source of air pollutant?
i-Industries ii-Power Plants iii-Automobile exhausts iv-All the above
c-Which gas is produced during incomplete combustion of fuels like petrol and diesel?
i-Carbon dioxide ii-Nitrogen iii-Carbon monoxide iv-Sulphur dioxide
d-Refrigerators, air conditioners and aerosol sprays have________pollutant.
i-CFCs ii-CCFs iii-FCCs iv-None of the above
Q.2.Write one word for the following:
a-Very small particles of solids and liquids suspended in air.
b-The gas released during burning of fossil fuels.
c-Two metals which are extremely harmful to the human beings.
d-Name the substance added to the filtered and aerated water to kill harmful germs.
e-The phenomenon of loss of dissolved Oxygen from water in water bodies.
Q.3.Define the following terms:
a- Pollution b- Acid rain c- Global warming d- Green house effect
Q.4. Answer the following questions in 30 words:
a-How do chlorofluorocarbons harm us?
b-Write 3 methods of reducing air pollution?
c-Mention the methods which might be helpful in conserving water.
d-Discuss various processes involved in the purification of water at home.
Q.5. Answer the following questions in 100 words:
a-Describe the greenhouse effect. Name two greenhouse gases.
b-Describe the harmful effects of acid rain.
c-What causes water pollution? How can the water pollution be prevented?
d-What should be the characteristics of potable water?
Q.6.Match the following:
a-Particulate pollutant i-Ozone layer
c-Green house gas iii-Jaundice/ Hepatitis
d-Polluted water iv-Conservation of water
e-Drip irrigation v-Flyash
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