Practice Test: Question Set - 02
1. Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxiate is ≥ __________ percent.
- (A) 84
- (B) 88
- (C) 80
- (D) 92
2. In water treatment plant, zeolite process is used to remove the __________ of water.
- (A) Acidity
- (B) Alkalinity
- (C) Hardness
- (D) Iron & zinc
3. Radioactive solid nuclear wastes are disposed off by
- (A) High temperature incineration
- (B) Pathological incineration
- (C) Pyrolysis
- (D) Underground burial in concrete containers
4. Disinfection of water is done to remove
- (A) Color
- (B) Bad taste
- (C) Foul odour
- (D) Bacteria
5. Which of the following is an adsorbent used for the removal of SO2 from gas/air?
- (A) Bog iron
- (B) Limestone powder or alkalised alumina
- (C) Silica gel
- (D) Active carbon
6. Noise level audible to audience sitting in the 5th row from the stage during a large orchestra show corresponds to about __________ decibels.
- (A) 105
- (B) 135
- (C) 160
- (D) 185
7. 'Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the
- (A) Industrial chimney exhaust
- (B) Automobiles exhaust
- (C) Photochemical reaction in polluted atmosphere
- (D) Burning of domestic fuel
8. The average thickness of ozone layer in stratosphere is about __________ dobson unit (DU).
- (A) 20
- (B) 230
- (C) 750
- (D) 1500
9. __________ plant emits large amount of SO2 as an air pollutant.
- (A) Nitric acid
- (B) Sulphuric acid
- (C) Chlor alkali
- (D) Iron & steel
10. CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing __________ molecules of ozone.
- (A) 102
- (B) 105
- (C) 109
- (D) 1015
11. The main type of sludge gas evolved during sewage treatment in Imhoff tank is
- (A) CO2
- (B) CH4
- (C) CO
- (D) H2
12. The upper layer of atmosphere is called the
- (A) Stratosphere
- (B) Troposphere
- (C) Ionosphere
- (D) None of these
13. Brown spots in fabrics will be caused by washing with water containing large amount of:
- (A) Iron
- (B) Zinc
- (C) Iodine
- (D) Bromine
14. The term Biological Oxygen Demand (BOD) is used in relation to
- (A) Potable water
- (B) Cooling water
- (C) Distilled water
- (D) Industrial effluents
15. Threshold limit value (TLV) of CO in air is __________ ppm.
- (A) 5
- (B) 50
- (C) 2000
- (D) 5000
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