1141. The earth’s atmosphere is an envelop of gases present upto a height of about ________ KMS:

A. 10
B. 200 *
C. 1000
D. 2000

1142. The density of the gases ( present in air) decreases with increasing altitude to such an extent that bout 70 % of the mass of atmospheric air is found in the lower 5KM of atmosphere . This lower region of atmosphere is called :

A. Ionosphere
B. Troposphere *
C. Stratosphere
D. None of these

1143. The upper layer of atmosphere is called :

A. Stratosphere *
B. Troposphere
C. Ionosphere
D. None of these

1144. Which of the following is not a natural source of air pollution ?

A. Volcanic eruptions and lightening discharges
B. Biological decay of vegetable matter
C. Photochemical oxidation of organic matter
D. None of these *

1145. Which of the following is a man made source of air pollution ?

A. Automobile exhaust *
B. Forest fire
C. Bacterial action in soil and swamp areas
D. All A B and C

1146. Which of the following sources is responsible for maximum air pollution ?

A. Industrial chimney exhaust
B. Forest fire
C. Automobiles exhaust *
D. Photochemical oxidation of organic matter

1147. Lagooning process is mainly a means of :

A. Sludge disposal *
B. Reduction of excessive flow in sewers
C. Biological treatment of wastes
D. None of these

1148. For existence of aquatic life in water , the dissolved oxygen content in it should not be less than ___________ ppm:

A. 10000
B. 5 *
C. 5000
D. 1000

1149. Which of the following is th most major constituents of air pollutants ?

A. Oxides of sulphur *
B. Oxides of nitrogen
C. Carbon monoxide
D. Hydrogen sulphide

1150. Sulphur dioxide present in the industrial chimney exhaust gases causes :

A. Respiratory and lung disease
B. Reduction in plant’s productivity owing to acid rain
C. Corrosion of building materials
D. All of the above