Practice Test: Question Set - 20
1. Tolerable limit of nitrogen oxides in air is __________ ppm.
- (A) 0.1
- (B) 1
- (C) 5
- (D) 25
2. Noise level heard at a distance of about 100 meters from a jet engine with after burner is about __________ decibels.
- (A) 120
- (B) 140
- (C) 170
- (D) 200
3. Presence of __________ in water stream are deleterious to aquatic life.
- (A) Soluble and toxic
organics
- (B) Suspended solids
- (C) Heavy metals and
cyanides
- (D) All (a), (b) &
(c)
4. 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
5. Noise emitted by a ventilation fan at a distance of 3 meters is about __________ decibels.
- (A) 85
- (B) 105
- (C) 125
- (D) 145
6. Main pollutant present in automobile exhaust is
- (A) CO
- (B) CO2
- (C) NO
- (D) Hydrocarbons
7. The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by
- (A) Biological oxygen
pond
- (B) Aerated lagoons
- (C) Trickling filters
- (D) Gravity separator
having oil skimming devices
8. Pollution by particulate matter emission in the atmosphere does not take place during metal
- (A) Grinding
- (B) Machining
- (C) Cutting
- (D) Polishing
9. Dose of chlorine for disinfection of water is about __________ mg/liter of water.
- (A) 0.01
- (B) 0.1
- (C) 0.3
- (D) 1
10. The commonest form of iron & manganese found in ground water as pollutant is in the form of their
- (A) Carbonates
- (B) Bi-carbonates
- (C) Chlorides
- (D) Sulphides
11. Solid content in most of the domestic sewage is about __________ percent.
- (A) 0.001
- (B) 0.1
- (C) 5
- (D) 10
12. Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools).
- (A) 1-2
- (B) 5-10
- (C) 15-20
- (D) 25-30
13. Which of the following pollutants is not emitted during volcanic eruptions?
- (A) SO2
- (B) H2S
- (C) CO
- (D) Hydrocarbons
14. Which is a secondary air pollutant?
- (A) Photochemical smog
- (B) Sulphur dioxide
- (C) Nitrogen dioxide
- (D) Dust particles
15. 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) 2000
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