Practice Test: Question Set - 16
1. Pick out the wrong statement.
- (A) Caustic embrittlement of boiler's metallic parts
is caused by high concentration of caustic soda in boiler feed water
- (B) Cooling and freezing of water kills the bacteria present in it
- (C) With increasing boiler operating pressure of
steam, the maximum allowable concentration of silica in feed water goes on
decreasing
- (D) Dissolved oxygen content in high pressure boiler feed water should
be nil
2. The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria.
- (A) Anaerobic
- (B) Saprophytic
- (C) Aerobic
- (D) Parasitic
3. Foul odour and bad taste of water is removed by treating with
- (A) Alum
- (B) Bleaching powder
- (C) Activated carbon
- (D) Copper sulphate
4. Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called
- (A) Fumes
- (B) Mists
- (C) Smoke
- (D) Aerosols
5. World environment day is observed every year on the 5th of
- (A) June
- (B) December
- (C) July
- (D) September
6. Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances.
- (A) Radioactive
- (B) Organic
- (C) Inorganic
- (D) None of these
7. Smoke is produced due to
- (A) Insufficient supply of combustion air and insufficient time for
combustion
- (B) Poor quality of fuel and improper mixing of fuel & combustion
air
- (C) Poor design & overloading of furnace
- (D) All (a), (b) and (c)
8. Septic tanks are used for the __________ of the deposited solids.
- (A) Separation
- (B) Anaerobic decomposition
- (C) Aerobic decomposition
- (D) None of these
9. Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about __________ decibels.
- (A) 20
- (B) 60
- (C) 90
- (D) 120
10. Which of the following is the most detrimental for water used in high pressure boiler?
- (A) Silica
- (B) Turbidity
- (C) Phenol
- (D) Dissolved oxygen
11. Automobile exhaust is passed through two compartments catalytic converter employing platinum as catalyst for
- (A) Conversion of CO into CO2 in the second compartment
- (B) Conversion of NOx into N2 and NH3 in
the first compartment
- (C) Oxidation of unburnt hydrocarbon fuel in the second compartment
- (D) All (a), (b) and (c)
12. Atmospheric pollution caused by the exhaust gas of supersonic transport air-crafts is mostly in the atmospheric region called
- (A) Thermosphere
- (B) Stratosphere
- (C) Troposphere
- (D) Mesosphere
13. The widest explosive limit is of __________, thereby making it the most explosive gas.
- (A) Acetylene
- (B) Petrol vapor
- (C) Hydrogen
- (D) Carbon monoxide
14. __________ is removed from water by lime-soda process.
- (A) Foul smell and taste
- (B) Iron and manganese
- (C) Temporary hardness
- (D) Permanent hardness
15. Presence of volatile compounds like gasoline, oil, alcohol, ether etc. in municipal sewers may cause
- (A) Explosion
- (B) Non biodegradable foam
- (C) Undesirable plant growth
- (D) Corrosion
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