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WorksheetsEVS - IV
Total questions: 50
Worksheet time: 25mins
1. Select the secondary air pollutants among the following :
a) ozone and carbon monoxide
b) peroxy-acyl-nitrate(PAN) and ozone
c) peroxy-acyl-nitrate(PAN) and carbon monoxide
d) carbon monoxide and sulphur dioxide
2. The primary pollutant caused by incomplete combustion of organic matter is
a) ozone
b) carbon monoxide
c) sulphur dioxide
d) none of the above
3. Select the primary air pollutant among the following :
a) sulphur dioxide and nitrogen oxides
b) ozone and carbon monoxide
c) sulphur dioxide and ozone
d) nitrogen oxide and ozone
4. The spray tower can be used to control
a) gaseous pollutants only
b) particulate pollutants only
c) both (a) and (b)
d) none of the above
5. The specific standard for SO2 under US Ambient Air Quality standards is 80 µg/m3 . This is approximately equivalent to
a) 0.03 ppm
b) 0.05 ppm
c) 0.08 ppm
d) 8 ppm
6. The depletion of ozone in the outer atmosphere may results in increased
a) heart attack cases
b) skin cancer cases
c) asthma cases
d) none of above
7. The rain is generally termed as acidic, if ph value of rain water falls below
a) 3
b) 5
c) 7
d) 8
8. The acid rains are caused by the following pollutants
a) SO2 and O3
b) SO2 and NOx
c) NOx and O3
d) CO and So2
9. To express sound levels in decibles, sound pressure levels are usually adopted on a reference scale of
a) 10 µPa
b) 20 µPa
c) 50 µPa
d) 100 µPa
10. The height of chimney required for effective disposal of 27 kg/hr of SO2 emission is
a) 42 m
b) 30 m
c) 222 m
d) 81 m
11. If the actual height of a stack is 150 m and plume height is 8m, then the effective height of the stack is
a) 150 m
b) 142 m
c) 158 m
d) 166 m
12. When the Adiabatic Lapse Rate (ALR) is more than Environmental Lapse Rate (ELR), then the ELR can be called as
a) super adiabatic lapse rate
b) sub adiabatic lapse rate
c) dry adiabatic lapse rate
d) wet adiabatic lapse rate
13. When Environmental Lapse Rate(ELR) is more than Adiabatic Lapse Rate (ALR), then the environment is said to be
a) stable
b) unstable
c) neutral
d) none of above
14. Temporary hardness in water is caused by the presence of
a) bicarbonate of Ca and Mg
b) sulphates of Ca and Mg
c) chloride of Ca and Mg
d) nitrates of Ca and Mg
15. Blue baby disease ( methemoglobinemia ) in children is caused by the presence of excess
a) chlorides
b) nitrates
c) fluorides
d) lead
16. Two sample of water A and B have pH values of 4.4 and 6.4 respectively. How many times acidic sample A is than sample B ?
a) 0
b) 50
c) 100
d) 200
17. If presents in water, chlorination of water does not reduced the
a) ammonia content
b) organic matter content
c) B.O.D
d) dissolved oxygen content
18. Dechlorination of water is achieved by adding
a) sodium thiosulphate
b) sodium sulphate
c) sodium hexametaphosphate
d) sodium bisulphate
19. the efficiency of a sedimentation tank does not depend upon
a) detention time
b) depth of the tank
c) length of the tank
d) horizontal velocity of water
20. A city supply of 15000 cubic metres of water per day is treated with a chlorine dosage of 0.5 ppm. For this purpose, the requirement of 25% bleaching powder per day would be
a) 300 kg
b) 75 kg
c) 30 kg
d) 7.5 kg
21. When the coefficient of rugosity is increased from 0.01 to 0.02, the gradient of a pipe of a given diameter to carry the same velocity will be
a) increased by 4 times
b) increased by 2 times
c) decreased by √2 times
d) decreased by 4 times
22. Which one of the following statements is true of trickling filter sludge ?
a) It has a comparatively low sludge volume index
b) It is more difficult to dewater than activated sludge
c) It has a comparatively low concentration of sludge solids
d) It is bulky
23. BOD is preferred to COD as an index of sewage concentration because
a) BOD represents both carbonaceous and nitrogenous organic matter while COD may indicate carbonaceous
b) BOD test is easier to perform and gives more reliable results
c) BOD relates specifically to putrescible organic matter which is the most objectionable sewage constituent
d) COD relates to the impurities which can only be removed by chemical treatment which is expensive
24. Under Indian conditions, the average per capita contribution of BOD is
a) 10 to 20 gm/d
b) 25 to 35 gm/d
c) 35 to 50 gm/d
d) 50 to 70 gm/d
25. Sewage sickness relates to
a) toxicity of sewage interfering with response to treatment
b) destruction of aquatic flora and fauna due to gross pollution of receiving bodies of water by sewage
c) reduction in the waste purifying capacity of the soil
d) clogging of pores in soil due to excessive application of sewage to land, obstructing aeration and landing to septic conditions
26. The chlorine demand of a water sample was bound to be 0.2 mg/l. The amount of bleaching powder containing 30% available chlorine to be added to treat one litre of such a water sample is
a) 0.67 mg
b) 0.06 mg
c) 1.33 mg
d) 0.14 mg
27. The ideal residual pressure at the farthest consumer’s tap in a properly designed water distribution system is in the range of
a) 0.016 to 0.020 N/mm2
b) 0.021 to 0.025 N/mm2
c) 0.026 to 0.030 N/mm2
d) 0.031 to 0.035 N/mm2
28. Under natural conditions of flow, an unpolluted river would contain
a) more dissolved oxygen in summer than in winter
b) less dissolved oxygen in summer than in winter
c) more or less the same amount of dissolved oxygen in winter and summer
d) the least amount of dissolved oxygen during the floods
29. For the combined sewerage system, egg-shaped sewers are preferred because
a) their construction is economical
b) they are structurally more stable
c) their maintenance is easier
d) they offer good flow velocity during the dry-weather-flow condition
30. An aeration basin with a volume of 400 m3 contains mixed liquor with suspended solid concentration of 1000 mg/l. The amount of mixed liquor suspended solids in the tank is
a) 500 kg
b) 250 kg
c) 600 kg
d) 400 kg
31. Taps are used in household drainage system to
a) prevent entry of foul gases in the house
b) restrict the flow of water
c) provide a partial vacuum
d) trap the solids wastes
32. Coal based thermal power stations pollute the atmosphere by adding
a) NOx and SO2
b) NOx, SO2 and SPM
c) NOx, SO2, SPM and CO
d) NOx, SPM and CO
33. Area method of land filling is most suitable when
a) area is unsuitable for excavation of trenches
b) adequate depth of cover material is available at the side
c) the water table is near the surface
d) natural or artificial depression exist in the vicinity
34. Two reservoirs at different levels are connected by two parallel pipes of diameter 2d and d. The ratio of the flows in the two pipes (large : smaller) is
a) √2 : 1
b) 2 : 1
c) 4 : 1
d) 4√2 : 1
35. If the total hardness and alkalinity of a sample of water are 300 mg/l and 100 mg/l (CaCO3 scale) respectively, then its carbonate and non-carbonate hardness (in units of mg/l) will be respectively
a) 100 and 200
b) 400 and 300
c) 100 and 4000
d) 400 and zero
36. Electrical conductivity (EC) of water and total dissolved solids (TDS) are interrelated. The value of EC will
a) decrease with increase in TDS
b) increase with increase in TDS
c) decrease initially and then increase with increase in TDS
d) increase initially and then decrease with increase in TDS
37. When two identical centrifugal pumps are operating in series on a common rising main, then
a) then pressure in the rising main will be nearly doubled, while the discharge will remain the same
b) the discharge will be nearly doubled, while the pressure in the rising main will be doubled
c) discharge as well as the pressure in the rising main will be doubled
d) discharge as well as the pressure in the rising main will increase but not become double
38. In transition of sewers from smaller diameters sewers to larger diameters sewers, the continuity of sewers is maintained at the
a) bottom of the concrete bed of sewers
b) inverts of the sewers
c) crowns of the sewers
d) hydraulic gradients of the sewers
39. The slope of a 1.0 m diameters concrete sewers laid at a slope of 1 in 1000, develops a velocity of 1 m/s, when flowing full. When it is flowing half-full, the velocity of flow through the sewers will be
a) 0.5 m/s
b) 1.0 m/s
c) √2 m/s
d) 2.0 m/s
40. One litre of sewage, when allowed to settle for 30 minutes gives a sludge volume of 27 cm3. If the dry weight of this sludge is 3.0 grams, the its sludge volume index will be
a) 9
b) 24
c) 30
d) 81
41.Which one of the following solid waste disposal methods is economically most acceptable ?
a) Sanitary landfill
b) Incineration
c) Composting
d) Pyrolysis
42. The construction of impounding reservoir is required when
a) average annual flow in the stream is lower than average demand
b) the rate of flow in the stream, in dry season is more than the demand
c) the rate of flow in the stream, in dry season is less than the demand
d) the rate of flow in the stream is equal to the demand
43 . The cleaning of slow sand filter is done by
a) reversing the direction of flow of water
b) passing air through the filters
c) passing a solution of alum and lime through the filters
d) scarping off top layers of sand and admitting water
44. Which one of the following would contain water with the maximum amount of turbidity ?
a) lakes
b) oceans
c) rivers
d) wells
45. The waste stabilization ponds can be
a) aerobic
b) anaerobic
c) facultative
d) none of the above
46. When was the water (Prevention and Control of Pollution) Act enacted by the Indian Parliament ?
a) 1970
b) 1974
c) 1980
d) 1985
47. The entry of soul smelling gases coming from the sewers can be prevented by
a) providing water seals for all the fixtures
b) providing water seals for all the fixtures and a vent pipe in the plumbing system
c) providing sufficient vent pipes in the plumbing system
d) exhaust fans
48. Ringelmann’s scale is used to
a) measure CO
b) measure SO2
c) grade density of smoke
d) grade automobile exhaust gas
49. Eutrophication of water bodies bodies is caused by the
a) discharge of toxic substance
b) excessive discharge of nutrients
c) excessive discharge of suspended
d) excessive discharge of chlorides
50. Non-disposal of solids waste may cause the spread of
a) malaria
b) rodents related plague
c) typhoid
d) dysentery
