46. Sound become hazardous noise pollution at level

1. 1. above 30 dB

   
   
   

   2. above dB

   
   
   

   3. above 100 dB

   
   
   

   4. above 120 dB

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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47. Fish die in water bodies polluted by sewage due to

1. 1. Pathogenes

   
   
   

   2. Clogging of gills by silts

   
   
   

   3. Reduction in oxygen

   
   
   

   4. Foul smell

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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48. Which of the following is not considered as air pollutan ?

1. 1. Hydrocarbon

   
   
   

   2. Carbon monoxide

   
   
   

   3. Carbon dioxide

   
   
   

   4. Sulphur dioxide

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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49. DDT is

1. 1. Green house gas

   
   
   

   2. Degradable pollutant

   
   
   

   3. Nondegradable pollutant

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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50. Pollutant likely to deplete ozone layer is

1. 1. Carbon monoxide

   
   
   

   2. Nitrogen Oxides

   
   
   

   3. Chloroglurocarbons

   
   
   

   4. Both b and C

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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