Noise level during normal conversation among men is about ______________ decibels?
Noise level during normal conversation among men is about ______________ decibels?
A. 10
B. 45
C. 90
D. 115
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Peroxyacetyl nitrate (PAN), a pollutant is found in the_________________?
Peroxyacetyl nitrate (PAN), a pollutant is found in the_________________?A. Automobile exhaust
B. Flue gas of coal based power plant
C. Exhaust of nitric acid plant
D. Exhaust of sulphuric acid plantThe average thickness of ozone layer in stratosphere is about _______________ dobson unit (DU)?
The average thickness of ozone layer in stratosphere is about _______________ dobson unit (DU)?A. 20
B. 230
C. 750
D. 1500What are the methods of treatment & disposal of radioactive wastes ?
What are the methods of treatment & disposal of radioactive wastes ?A. Evaporation & chemical precipitation
B. Biological methods & adsorption in ion exchange materials
C. Fixing into a solid mass with cement and sinking deep in the sea
D. All A., B. & C.Photochemical smog is formed from automobile exhaust ________________?
Photochemical smog is formed from automobile exhaust ________________?A. By reaction of hydrocarbon & nitric oxide in presence of sunlight
B. Appears only on sunny days
C. Is harmful for crops and trees also besides causing eye irritation & asthma
D. All A., B. & C.Which is the most practical and economical method for removal of suspended solid matter from polluted water ?
Which is the most practical and economical method for removal of suspended solid matter from polluted water ?A. Sedimentation
B. Skimming off
C. Chlorination
D. Biological oxidationDisinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of_________________?
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.