High noise levels produced during operation of fans and compressors can be reduced by using
A. Mufflers (silencers)
B. Accoustical absorbent
C. Lagging of noisy duct
D. None of these
Answer: Option A
A. Mufflers (silencers)
B. Accoustical absorbent
C. Lagging of noisy duct
D. None of these
Answer: Option A
Fluorosis is caused due to the presence of excessive amount of __________ in drinking water.
A. Mercury
B. Lead
C. Fluoride
D. Arsenic
Smog is not formed due to the presence of __________ in the atmosphere.
A. SO2
B. NOx
C. CO2
D. Any of these
Dose of chlorine for disinfection of water is about __________ mg/litre of water.
A. 0.01
B. 0.1
C. 0.3
D. 1
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