2
MCQ (Single Correct Answer)
Photochemical smog occurs in warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog, identify it.
A
NO$$_2$$
B
O$$_3$$
C
SO$$_2$$
D
Unsaturated hydrocarbon
3
MCQ (Single Correct Answer)
Which of the following statements is not true about classical smog?
A
Its main components are produced by the action of sunlight on emissions of automobiles and factories
B
Produced in cold and humid climate
C
It contains compounds of reducing nature
D
It contains smoke, fog and sulphur dioxide
4
MCQ (Single Correct Answer)
Biochemical Oxygen Demand, (BOD) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be
A
rich in dissolved oxygen
B
poor in dissolved oxygen
C
highly polluted
D
not suitable for aquatic life
5
MCQ (Single Correct Answer)
Which of the following statement(s) is/are wrong?
A
Ozone is not responsible for green house effect
B
Ozone can oxidise sulphur dioxide present in the atmosphere to sulphur trioxide
C
Ozone hole is thinnig of ozone layer present in stratosphere
D
Ozone is produced in upper stratosphere by the action of $U V$ rays on oxygen
6
MCQ (Single Correct Answer)
Sewage containing organic waste should not be disposed in water bodies because it causes major water pollution. Fishes in such a polluted water die because of
A
large number of mosquitoes
B
increase in the amount of dissolved oxygen
C
decrease in the amount of dissolved oxygen in water
D
clogging of gills by mud