Photochemical smog was first observed in -

(1) London

(2) Los Angeles

(3) Paris

(4) Tokyo

An increase in $C{O}_2$ concentration in the atmosphere will result in

(1) Adverse effects of natural vegetation

(2) Global warming

(3) Temperature decrease in a global atmosphere

(4) Genetic disorders in plants and animals

Domestic waste will lead to : 

1. Biodegradable pollution

2. Nondegradable pollution

3. Thermal pollution of soil

4. Air pollution

The major source of BOD in the river Ganga is 

(1) Leaf litter

(2) Fishes

(3) Human waste

(4) Aquatic plants

If a lake is contaminated with DDT, it's highest concentration would be found in :

1. Primary consumer

2. Secondary consumer

3. Tertiary consumer

4. None of the above.

The most harmful air pollutant produced by automobiles is:

1. $HN{O}_2$

2. $N{O}_X$

3. $S{O}_2$

4. CO

Sewage water can be purified by

(1) Aquatic plant

(2) Microorganism

(3) Penicillin

(4) Fishes

Major pollutant in Jet plane emission is -

(1) $S{O}_2$

(2) CFC

(3) CO

(4) $CC{l}_4$

B.O.D is-

What is the intensity of sound in normal conversation 

1. 10 -20 decibal

2. 30 - 60 decibal

3. 70 - 90 decibal

4. 120 - 150 decibal