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 Multiple Choice QuestionsMultiple Choice Questions

81.

Photosynthetic Active Radiation (PAR) has the following range of wavelengths

  • 400- 700 nm

  • 450- 950 nm

  • 340- 450 nm

  • 500- 600 nm


82.

The gases that produce green house gases are

  • CH4, CFCs, CO2

  • CO2, N2O, H2

  • CFCs, NO2, O2

  • CO2, N2, water vapour


83.

Which of the following statement is correct about DDT

  • It is a biomagnifying biodegradable pollutant

  • It is non biomagnifying biodegradable pollutant

  • It is biomagnifying non biodegradable pollutant

  • It is not a pollutant


84.

CO is a pollutant because

  • it reacts with O2

  • it inhibits glycolysis

  • it reacts with haemoglobin

  • it makes nervous system inactive


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85.

A large quantity of urban sewage is drained into nearby village river. Which among the given conditions would happen after mixing of sewage into the river

(i) Biochemical oxygen demand (BOD) of receiving water body increases.

(ii) Dissolved oxygen of receiving water body decreases.

(iii) It will not cause mortality among fishes and other aquatic creatures.

(iv) It will lead to nutrient enrichment of receiving water body.

  • (i), (ii) and (iii)

  • (i), (ii) and (iv)

  • (ii) and (iii) only

  • (iii) and (iv) only


B.

(i), (ii) and (iv)

When sewage, having biodegradable organic matter is released into the water body, microorganisms involved in biodegradation of organic matter (in the receiving water body) consume a lot of oxygen to decompose the sewage and as a result there would be a sharp decline  in dissolved oxygen downstream from the point of sewage discharge and biological oxygen demand (BOD) would increase. Presence of sewage causes nutrient enrichment (large amount of nutrients) in water which causes excessive growth of planktonic (free floating) algae, called algal bloom. Algal bloom causes deterioration of water quality and fish mortality.


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86.

Which country has the greatest contribution for the hole formation in ozone layer?

  • USA

  • Germany

  • Russia

  • Japan


87.

One greenhouse gas contributes 14% to total global warming and another contributes 6%. These are respectively identified as

  • N2O and CO2

  • CFCs and N2O

  • methane and CO2

  • methane and CFCs


88.

Assertion: BOD of a river polluted by sewage is more than 20 ppm.

Reason: Polluted river contains excess of organic matter.

  • If both assertion and reason are true and reason is the correct explanation of assertion. 

  • If both assertion and reason are true but reason is not the correct explanation of assertion. 

  • If assertion is true but reason is false. 

  • If both assertion and reason are false.


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89.

Plants do not get benefit from

  • N2 in air

  • O2 in air

  • CO2 in air

  • O3 in air


90.

Assertion: Secondary air pollutants are formed by interaction among the primary pollutants and are more toxic.

Reason: DDT is a secondary air pollutant.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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