(A) insufficient supply of combustion air and insufficient time for combustion.
(B) poor quality of fuel and improper mixing of fuel & combus
(C) poor design & overloading of furnace.
(D) all (a), (b) and (c).
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12 >>Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air. ?
(A) hydrocarbons
(B) hydrogen flouride
(C) hydrogen sulphides
(D) nitrogen dioxide
13 >>Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO2�in air is __________ ppm. ?
(A) 5
(B) 500
(C) 1000
(D) 5000
14 >>Main pollutants released from iron & steel industry is ?
(A) CO, CO2 & SO2.
(B) H2S, NO & SO3.
(C) CO2, H2S & NO2.
(D) SO3, NO2 & CO2.
15 >>Exposure to chemicals having carcinogenic properties cause ?
(A) dermatitis (skin disorder)
(B) cancer
(C) asphyxiation (suffocation)
(D) asthma
16 >>Scale formation in boiler is controlled by ?
(A) preheating of feed water.
(B) reduction in hardness, silica & alumina in feed water.
(C) keeping the pH value of feed water just below 7.
(D) eliminating H2S in feed water.
17 >>Noise level heard at a distance of about 100 metres from a jet engine with after burner is about __________ decibels. ?
(A) 120
(B) 140
(C) 170
(D) 200
18 >>TLV of mercury in potable (drinking) water is about __________ ppm. ?
(A) 0.001
(B) 0.1
(C) 1
(D) 5
19 >>Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)? ?
