Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is _______________ micro gram (μ g)/litre?
(A) 22
(B) 42
(C) 332
(D) 1050
Which of the following fine dust removal equipments is the most efficient ?
(A) Bag filter
(B) Scrubber
(C) Electrostatic precipitator
(D) Cyclone separator
Noise level in a quiet private business office is about _____________ decibels?
(A) 25
(B) 50
(C) 70
(D) 85
Which of the following is not a weightless pollutant ?
(A) SPM
(B) Thermal pollution
(C) Radioactive rays
(D) Noise pollution
Noise pollution level in a chemical plant is expressed in __________________?
(A) Roentgen
(B) Decibel
(C) Hertz
(D) None of these
Smog is ______________________?
(A) Nothing but black smoke
(B) A combination of smoke and fog
(C) A liquid particle resulting from vapor condensation
(D) A solid particle
(D) g. fly-ash
Pick out the wrong statement ?
(A) Addition of methane to the furnace atmosphere reduces decarburising by hydrogen
(B) Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon gases carburise the surface of steel at annealing temperatures
(C) Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation with increase in surface hardness
(D) None of these
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
Ringelmann chart No. 2 corresponds to _______________ percent black smoke?
(A) 10
(B) 20
(C) 40
(D) 80
Global warming may result in __________________?
(A) Flood
(B) Cyclone
(C) Decrease in food productivity
(D) All