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

Which of the following is the most widely used disinfectant in water treatment ?

A. Chlorine
B. Irradiation of water by ultraviolet light
C. Cation exchanger
D. Coagulation

There are five concentric layers within the atmosphere which is differentiated on the basis of temperature. The atmospheric layer which lies close to the earth’s surface in which human being along with other organisms live is called troposphere. The rate at which air temperature in the troposphere gradually decreases with height is about _____________ °C/km?

A. 0.05
B. 1
C. 6.5
D. 15

Threshold limit value (TLV) of CO in air is _____________ ppm?

A. 5
B. 50
C. 2000
D. 5000

Ethanolamine is an absorbent used for the removal of _____________ from air/gas?

A. HF
B. SO2
C. H2S
D. Both B. & C.

Which is the most efficient dust removal equipment for removal of submicronic dust particles from blast furnace gas ?

A. Packed scrubber
B. Gravity settling chamber
C. Electrostatic precipitator
D. Hydrocyclone

Presence of nitrates in water in excess of 50 ppm causes________________?

A. Methemoglobinemia
B. Gastroenteritis
C. Asphyxiation
D. Tooth decay

Black smoke coming out of the chimney of a furnace is an indication of the use of ______________ in the furnace?

A. Low amount of excess combustion air
B. Large quantity of excess combustion air
C. Hydrocarbon fuel
D. Pulverised coal as fuel

Biological oxidation ponds remove organic matters present in the polluted water by _______________?

A. Using the activities of bacteria and other micro organisms
B. Aerobic oxidation
C. Both A. & B.
D. Neither A. nor B.

Which of the following plants does not emit appreciable amount of SO2 in atmosphere ?

A. Thermal power plant
B. Petroleum refinery
C. Nitric acid plant
D. Sulphuric acid plant