Oilish impurities present the effluent discharged from the electroplating industry is normally not removed by _____________________?

A. Chemical coagulation
B. Floatation & skimming
C. Centrifugation
D. Ultra filtration

______________ content of the phosphate rock is the pollutant of primary interest in a phosphatic fertiliser plant ?

A. Calcium
B. Fluorine
C. Phosphorous
D. Sulphur

The weakest sound that can be heard by a person in a quiet environment is equivalent to ____________ decibel ?

A. 1
B. 5
C. 10
D. 50

Workers working in _______________ industry are most prone to white lung cancer?

A. Coal mining
B. Limestone mining
C. Textile
D. Asbestos

Which of the following is a manmade source of air pollution ?

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

Which of the following is the most active zone of atmosphere in which weathering events like rain, storm & lightning occur ?

A. Thermosphere
B. Troposphere
C. Stratosphere
D. None of these

Lung cancer & DNA breakage are the major ill effects of excessive ozone exposure to human beings. Ozone layer depletion in the atmosphere is mainly caused by the presence of________________?

A. CO2
B. SO2
C. Hydrocarbons
D. CFC (chloro fluoro carbon)

The function of skimming tank in sewage treatment is to remove _____________ substances?

A. Dissolved solid
B. Suspended solid
C. Oil & fatty
D. Gritty & inorganic

A standard test for determination of hardness in water is termed as ______________ test?

A. EDTA
B. Electometric
C. Total count
D. Presumptive

Removal of ______________ results from the disinfection of water?

A. Turbidity
B. Odour
C. Hardness
D. Bacteria