______________ is the process of killing organism in water ?

A. Coagulation
B. Sterilisation
C. Disinfection
D. Sedimentation

Salt content in sea water is about ______________ percent?

A. 0.5
B. 1
C. 3.5
D. 9.05

High noise levels produced during operation of fans and compressors can be reduced by using__________________?

A. Mufflers (silencers)
B. Acoustic absorbent
C. Lagging of noisy duct
D. None of these

Green house gases blanket/block the infrared radiation from earth’s surface to the atmosphere leading to its progressive warming up. Which of the following gases does not exhibit green house effect ?

A. CO2
B. H2
C. SO3
D. N2

Which of the following is an adsorbent for removal of nitrogen oxides from gas/air ?

A. Active carbon
B. Silica gel
C. Bog iron (iron oxide)
D. Pulverised limestone

The effect of increase in carbon dioxide level of the atmosphere and its profound effect on our climate is called the ________________?

A. Catalytic conversion
B. Green house effect
C. Global warming
D. Both B. and C.

Which of the following is not a practical method of low level radioactive waste disposal ?

A. Dilution with inert material
B. Discharging to atmosphere through tall stacks after dilution
C. Disposing off in rivers & oceans
D. Filling in steel crates and shooting it off out of earth’s gravity

Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of_________________?

A. Ozone and iodine
B. Chlorine or its compounds
C. Ultraviolet light for irradiation of water
D. All A., B. & C.

Global warming may result in __________________?

A. Flood
B. Cyclone
C. Decrease in food productivity
D. All A., B. and C.

Ringelmann chart No. 2 corresponds to _______________ percent black smoke?

A. 10
B. 20
C. 40
D. 80