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Public Health Engineering Multiple Choice Questions
1. The presence of
A. iron
B. manganese
C. sodium fluoride
D. calcium carbonate
Answer: A. iron
2. The maximum permissible chlorine content for public supplies should be between
A. 0.1 to 0.2 ppm
B. 0.3 to 0.4 ppm
C. 1.2 to 4 ppm
D. 6.5 to 8 ppm
Answer: A. 0.1 to 0.2 ppm
3. Slow sand filter requires
A. more
B. less
Answer: A. more
4. Air vent pipe is not essentially required in a septic tank.
A. True
B. False
Answer: B. False
5. The pocess of excluding large sized particles from water with the help of screens is called filteration.
A. Yes
B. No
Answer: B. No
6. A pipe installed for ventilation purpose is called
A. waste pipe
B. soil pipe
C. vent pipe
D. anti-siphonage pipe
Answer: C. vent pipe
7. The presence of calcium and magnesium chloride in water causes
A. softening
B. bad taste
C. hardness
D. turbidity
Answer: C. hardness
8. In the process of screening, the screens should be inclined at an angle of
A. 10? to 20?
B. 30? to 40?
C. 45? to 60?
D. 70? to 85?
Answer: C. 45? to 60?
9. To prevent the formation of crystalline hydrates of ‘Ice’ of chlorine, the chlorine supply cylinders are kept at a temperature from
A. 10?C to 20?C
B. 20?C to 27?C
C. 27?C to 37?C
D. 38?C to 42?C
Answer: D. 38?C to 42?C
10. When chlorine is added to raw water at more than one point, the process is termed as break point chlorination.
A. Right
B. Wrong
Answer: B. Wrong
11. Manholes on sewer lines are provided for
A. periodic cleaning
B. providing air for oxidation
C. removal of part of sewerage
D. all of these
Answer: A. periodic cleaning
12. The length of rectangular sedimentation tank should not be more than
A. twice
B. three times
C. four times
D. six times
Answer: C. four times
13. The most commonly used chemical for dechlorination of water is
A. sodium thiosulphate
B. sodium sulphite
C. potassium permaganate
D. all of these
Answer: D. all of these
14. The discharge from washing places is called sullage.
A. True
B. False
Answer: A. True
15. The portion of soil through which lateral movement of water takes place is called
A. water tablean aquiclude
B. an aquiclude
C. zone of saturation
D. none of these
Answer: C. zone of saturation
16. A septic tank is a
A. sedimentation tank
B. digestion tank
C. combination of sedimentation and digestion tank
D. aeration tank
Answer: C. combination of sedimentation and digestion tank
17. Under steady low heads
A. reciprocating
B. centrifugal
Answer: B. centrifugal
18. The maximum permissible total solid content in water for domestic purposes should not exceed
A. 300 ppm
B. 400 ppm
C. 500 ppm
D. 1000 ppm
Answer: C. 500 ppm
19. Cleaning of rapid sand filters is done by
A. scraping the top layer of filter media
B. back washing
C. providing new sand layers
D. all of these
Answer: B. back washing
20. The sand, used for filteration, should not loose weight more than
A. 2.50%
B. 5%
C. 7.50%
D. 10%
Answer: B. 5%
21. Bleaching powder is
A. slaked lime
B. chloride of lime
C. hypo-chloride of lime
D. hypo-chlorite of lime
Answer: D. hypo-chlorite of lime
22. The efficiency of sedimentation tank for a given discharge, can be increased by
A. increasing the depth of tank
B. decreasing the depth of tank
C. increasing the surface area of tank
D. decreasing the surface area of tank
Answer: C. increasing the surface area of tank
23. Absolute pure water is good for health.
A. Right
B. Wrong
Answer: B. Wrong
24. The most important source of water for public water supply is
A. lake
B. pond
C. river
D. sea
Answer: D. sea
25. The most common cause of acidity in water is
A. hydrogen
B. oxygen
C. carbon dioxide
D. all of these
Answer: C. carbon dioxide
26. Water is
A. safe
B. harmful
Answer: B. harmful
27. The temporary hardness due to calcium bicarbonates can be removed by
A. boiling
B. lime process
C. lime-soda process
D. zeolite process
Answer: A. boiling
28. Which of the following statement is correct?
A. The pumping system is the best system of water distribution.
B. A sluice valve prevents water to flow back in the opposite direction
C. In a ring system, there is one main supply pipe.
D. all of the above
Answer: C. In a ring system, there is one main supply pipe.
29. The minimum diameter of a manhole cover should be
A. 25 m
B. 50 cm
C. 75 cm
D. 100 cm
Answer: B. 50 cm
30. An egg-shaped cross-section of a sewer
A. is economical than circular cross-section
B. is more stable than circular cross-section
C. provides self cleaning velocity in dry weather
D. none of the above
Answer: C. provides self cleaning velocity in dry weather
31. Garbage is a
A. dry waste
B. semi-liquid waste
C. liquid waste
D. none of these
Answer: A. dry waste
32. The human excreta is a
A. dry
B. semi-liquid
C. liquid
Answer: B. semi-liquid
33. The increase in population of a young and rapidly developing city is estimated by comparative method.
A. True
B. False
Answer: B. False
34. The lime soda process of water softening
A. requires less quantity of coagulant
B. helps in kolling pathogenic bacterias
C. is suitable for turbid and acidic water
D. all of these
Answer: D. all of these
35. Odours and tastes may result due to the prsence of
A. micro-organisms either dead or alive
B. dissolved gases such as oxygen, carbon dioxide, methane etc.
C. mineral substances such as sodium chloride, iron compounds etc.
D. all of the above
Answer: D. all of the above
36. The lower portion of a manhole is is known as
A. access shaft
B. base
C. working chamber
D. cover
Answer: E.
37. Which of the following statement is wrong?
A. The water carriage system is more hygienic.
B. There is no smell or sight nuisance in the case of water carriage system.
C. The sewers in the water carriage system being all underground do not impair the beauty of the place
D. The initial cost of construction of water carriage system is very low.
Answer: D. The initial cost of construction of water carriage system is very low.
38. Land disposal of sewage will be favourable where
A. the rivers run dry or have a small flow during summer
B. rainfall is very high
C. climate is wet and rates of evaporation is low
D. all of the above
Answer: A. the rivers run dry or have a small flow during summer
39. The amount of residual chlorine in treated water is determined by the
A. Orthotolodine test
B. Iodemetric test
C. Amperometric test
D. all of these
Answer: D. all of these
40. When in the pervious strata, the surface of water surrounding the well is at atmospheric pressure, the well is known as
A. gravity well
B. artesian well
C. open well
D. deep well
Answer: A. gravity well
41. The natural outflow of sub-surface water at the surface is termed as spring.
A. Correct
B. Incorrect
Answer: A. Correct
42. When turbidity of water exceeds about 45 ppm, coagulation
A. should be
B. should not be
Answer: A. should be
43. Manholes are, generally, located
A. at all changes of direction
B. at all changes of gradient
C. at all junctions of main and branch sewers
D. all of these
Answer: D. all of these
44. The bacteria which require oxygen for their survival is known as
A. anaerobic bacteria
B. pathogenic bacteria
C. aerobic bacteria
D. non-pathogenic bacteria
Answer: C. aerobic bacteria
45. The turbidity in water is caused due to
A. silt
B. clay
C. finely divided organic matter
D. all of these
Answer: D. all of these
46. The process of removing excess chlorine from water is called
A. plain chlorination
B. post-chlorination
C. dechlorination
D. super-chlorination
Answer: C. dechlorination
47. The coefficient of uniformity for slow sand filters is
A. 1.35
B. 1.55
C. 1.75
D. 2.05
Answer: C. 1.75
48. In a rapid sand filter, the filter head varies from
A. 1 to 1.5 m
B. 1.5 to 2 m
C. 2 to 4 m
D. 4 to 5 m
Answer: C. 2 to 4 m
49. For a city or town with roads of rectangular pattern, the type of layout used for the distribution of pipes is
A. dead end system
B. ring system
C. radial system
D. grid iron system
Answer: D. grid iron system
50. The type of joint to be used in pipes depends upon the
A. material of pipe
B. internal pressure
C. conditions of support
D. all of these
Answer: D. all of these
51. Grit chambers are used to remove sand and other organic matter from sewage.
A. Agree
B. Disagree
Answer: A. Agree
52. The water supply system means
A. the entire scheme of collection and disposal of liquid waste
B. the complete layout from the source of supply to the distribution
C. construction of reservoirs
D. construction of canals
Answer: B. the complete layout from the source of supply to the distribution
53. The process of dechlorination is followed by
A. pre-chlorination
B. post cholorination
C. super chlorination
D. double chlorination
Answer: C. super chlorination
54. Suspended impurities cause turbidity in water.
A. Yes
B. No
Answer: A. Yes
55. The horizontal tunnels constructed at shallow depths along the banks of a river to intercept the ground water table are called
A. canals
B. infiltration galleries
C. springs
D. lakes
Answer: B. infiltration galleries
56. Air binding means accumulation of
A. air
B. impurities
Answer: A. air
57. The yield of a rapid sand filter is
A. 10 times
B. 15 times
C. 20 times
D. 30 times
Answer: D. 30 times
58. Calcium sulphate present in water causes corrosion.
A. True
B. False
Answer: A. True
59. The water which leaks into sewers from the ground is termed as infiltration.
A. Yes
B. No
Answer: A. Yes
60. When the pO value of water is 5, then it has
A. no perceptible odour
B. distinct odour
C. faint odour
D. extremely strong odour
Answer: D. extremely strong odour
61. Pre-chlorination
A. improves coagulation
B. reduces odours
C. reduces tastes
D. all of these
Answer: D. all of these
62. The activated sludge process of sewage treatment
A. requires smaller area for construction of whole unit
B. requires smaller water head for operation than trickling filters
C. has high efficiency
D. all of the above
Answer: D. all of the above
63. Turbidity of water is expressed in terms of
A. silica scale
B. platinum cobalt scale
C. pO value
D. none of these
Answer: A. silica scale
64. The temporary hardness in water is cused due to the salts like
A. chlorides
B. nitrates
C. carbonates
D. sulphates
Answer: C. carbonates
65. A valve which allows the water to flow in one direction but prevents its flow in the reverse direction, is known as
A. sluice valve
B. reflux valve
C. air relief valve
D. pressure relief valve
Answer: B. reflux valve
66. The rate of filteration
A. increases
B. decreases
Answer: B. decreases
67. The pipe joint commonly used in pumping stations is
A. flexible joint
B. flanged joint
C. expansion joint
D. spigot and socket joint
Answer: B. flanged joint
68. The maximum permissible chloride content in water for domestic supplies should not exceed
A. 250 ppm
B. 350 ppm
C. 450 ppm
D. 550 ppm
Answer: A. 250 ppm
69. For high and fluctuating heads
A. reciprocating
B. centrifugal
Answer: A. reciprocating
70. The vertical wells provided along the banks of a river to draaw ground water in dry season are called
A. Open wells
B. tube wells
C. artesian wells
D. infiltration wells
Answer: D. infiltration wells
71. When manganese is present in water, it reduces the degree of hardness.
A. Yes
B. No
Answer: B. No
72. When the chlorine is added beyond the break point, the process of treating the water is known as
A. plain chlorination
B. post-chlorination
C. dechlorination
D. super-chlorination
Answer: D. super-chlorination
73. The arithmetical increase method of forecasting population gives
A. same value
B. lesser value
C. higher value
Answer: B. lesser value
74. The yield of a surface stream may be obtained by
A. cross-section velocity method
B. strem gauging
C. chemical method
D. all of these
Answer: D. all of these
75. The natural process in which the oxygen of water of streams is consumed by sewage and at the same time, it is replenished (filled again) by the atmosphere, is known as
A. oxidation
B. deoxidation
C. self purification
D. sedimentation
Answer: C. self purification
76. Biological action is used in
A. screens
B. sedimentation tanks
C. trickling filters
D. all of these
Answer: C. trickling filters
77. Slow sand filter is more efficient for the removal of
A. bacteria
B. odour
C. turbidity
D. all of these
Answer: A. bacteria
78. Water test is conducted for house plumbings.
A. Yes
B. No
Answer: B. No
79. The average consumption of water for commercial use varies from 20 to 25% of total consumption.
A. Yes
B. No
Answer: A. Yes
80. The water obtained from the tube wells is known as
A. surface water
B. sub-surface water
C. run-off
D. potable water
Answer: B. sub-surface water
81. In lime soda process, the pH value of treated water is increased.
A. True
B. False
Answer: A. True
82. The water obtianed from
A. rains
B. rivers
C. reservoirs
D. artesian wells
Answer: D. artesian wells
83. Rapid sand filter can remove bacterias upto an extent of
A. 60% to 70%
B. 70% to 80%
C. 80% to 90%
D. 90% to 99%
Answer: C. 80% to 90%
84. Wrought iron pipes are more costly and are
A. less
B. more
Answer: A. less
85. Suspended impurities consist of
A. iron
B. chlorine
C. bacteria
D. all of these
Answer: C. bacteria
86. The water bearing strala i.e. layers of sand, gravel etc, is called
A. an acquifer
B. an aquiclude
C. an aquifuge
D. zone of saturation
Answer: A. an acquifer
87. The area of the openings in screens should be such that the velocity of flow through them does not exceed
A. 0.75 to 1 m/s
B. 1.5 to 3 m/s
C. 3 to 5 m/s
D. 5 to 6 m/s
Answer: A. 0.75 to 1 m/s
88. In secondary treatment of sewage, the operation which takes place is
A. removal of heavier suspended inorganic material
B. removal of fine dissolved organic material
C. removal of harmful bacterias
D. all of the above
Answer: B. removal of fine dissolved organic material
89. The presence of hydrogen sulphide in water causes
A. softening
B. alkalinity
C. aciity
D. bad taste
Answer: C. aciity
90. Which of the following statement is wrong?
A. The quality of tube well water is better than that of surface sources.
B. The discharge of tube well is more than that of an open well.
C. The tube well should not derive water from the first pervious strata.
D. none of the above
Answer: D. none of the above
91. The water from kitchens, bathrooms, wash basins is called
A. sewage
B. sullage
C. raw sewage
D. none of these
Answer: B. sullage
92. The pipe installed in the house or building drainage to preserve the water seal of a trap is called anti-siphonage pipe.
A. Right
B. Wrong
Answer: A. Right
93. Rapid sand filters are cheap and economical as compared to slow sand filters.
A. True
B. False
Answer: A. True
94. The suitable layout of a distribution system for well planned cities is
A. dead end system
B. ring system
C. radial system
D. grid iron system
Answer: B. ring system
95. Crystalline hydrates of ‘Ice” of chlorine are formed at a temerature of
A. below 10?C
B. 15?C
C. 20?C
D. above 20?C
Answer: A. below 10?C
96. The coagulation is not required in
A. slow sand
B. rapid sand
Answer: A. slow sand
97. The detention time for an ordinary plain sedimentation tank is
A. 1 to 2 hours
B. 2 to 4 hours
C. 6 to 8 hours
D. 20 to 24 hours
Answer: C. 6 to 8 hours
98. The alum when mixed with water as a coagulant,
A. does not effect pH value of water
B. decreases pH value of water
C. increases pH value of water
D. none of these
Answer: B. decreases pH value of water
99. Which of the following statement is correct?
A. Slow sand filters work under atmospheric pressure.
B. Rapid sand filters require coagulation.
C. Rapid sand filters should be cleaned after 2 to 3 days
D. all of the above
Answer: D. all of the above
100. The quality of tube well water is
A. good
B. poor
Answer: A. good
101. Egg-shaped sewers are generally used for
A. separate system
B. combined system
C. partially separate system
D. all of these
Answer: D. all of these
102. Grit chambers of a sewage plant are usually changed after
A. 1 day
B. 1 week
C. 2 weeks
D. 4 weeks
Answer: C. 2 weeks
103. Low turbidity of water can be determined by
A. turbidity tube
B. Jacksons turbidimeter
C. Baylis turbidimeter
D. Hellipe turbidimeter
Answer: C. Baylis turbidimeter
104. High turbidity of water can be determined by
A. turbidity tube
B. Jacksons turbidimeter
C. Baylis turbidimeter
D. Hellipe turbidimeter
Answer: B. Jacksons turbidimeter
105. The maximum permissible hardness in water for drinking purposes should not exceed 100 ppm.
A. Correct
B. Incorrect
Answer: A. Correct
106. When the pH value of water is more than 7, it represents
A. neutal
B. acidic
C. alkaline
Answer: C. alkaline
107. Copper sulphate is the most common chemical used for controlling
A. bacteria
B. algae
C. silt
D. mineral matter
Answer: B. algae
108. Flush type fire hydrants remain standing above the road.
A. Correct
B. Incorrect
Answer: B. Incorrect
109. Rapid sand filter can remove turbidity from water upto an extent of
A. 15 to 25 ppm
B. 25 to 35 ppm
C. 35 to 40 ppm
D. 40 to 50 ppm
Answer: C. 35 to 40 ppm
110. Bio-chemical oxygen demand (B.O.D.) of safe drinking water must be
A. 0
B. 10
C. 50
D. 100
Answer: A. 0
111. Sphere shaped bacterias are called
A. spirilla
B. bacilli
C. cocci
D. trichobacteria
Answer: C. cocci
112. A sewer which receives storm water, surface run-off and sewage is called a
A. common sewer
B. combined sewer
C. branch sewer
D. outfall sewer
Answer: B. combined sewer
113. The amount of oxygen consumed by sewage from an oxidising agent like potassium dichromate is termd as
A. bio-chemical oxygen demand (B.O.D.)
B. chemical oxygen demand (C.O.D.)
C. relative stability
D. none of these
Answer: B. chemical oxygen demand (C.O.D.)
114. A separate system will be favourable when
A. the sewers are to be laid in rocks
B. the finances are limited
C. the topography is flat necessitating deep excavation for combined sewers
D. all of the above
Answer: D. all of the above
115. The valve provided on the suction pipe in a tube well is
A. sluice valve
B. air relief valve
C. pressure relief valve
D. reflux valve
Answer: D. reflux valve
116. The equipment used for cleaning the sewers easily is called
A. gouge
B. scoop
C. claw
D. scraper
Answer: D. scraper
117. The water obtianed from
A. infiltration galleries
B. springs
C. rivers
D. wells
Answer: B. springs
118. Which of the following statement is correct?
A. Screens are inclined to increase the opening area.
B. Plain sdimentation is useful as a process preliminary to further treatments.
C. Ratio of the volume of the basin of sedimentation tank to the rate of flow is called detention period
D. all of the above
Answer: D. all of the above
119. According to Indian standards, the consumption of water per capita per day for nursing homes, boarding schools and hostels is
A. 85 litres
B. 100 litres
C. 115 litres
D. 135 litres
Answer: D. 135 litres
120. The equipment used for removing paper and rags from sewers is called
A. gouge
B. scoop
C. claw
D. scraper
Answer: C. claw
121. Run-off is the water which flows
A. in infiltration galleries
B. in sewer pipes
C. due to leakage of pipes
D. in rivers
Answer: D. in rivers
122. In preliminary treatment of sewage, the operation which takes place, is
A. removal of fine suspended particles
B. removal of fine dissolved organic material
C. removal of lighter floating material
D. removal of harmful bacterias and other organisms
Answer: C. removal of lighter floating material
123. The hydrants are used for tapping waer from mains for
A. fire extinguishing
B. street washing
C. flushing sewer lines
D. all of these
Answer: D. all of these
124. The presence of calcium and magnesium bi-carbonates in water causes hardness in the water.
A. Correct
B. Incorrect
Answer: A. Correct
125. The acration of water is done to remove
A. colour
B. odour
C. taste
D. all of these
Answer: D. all of these
126. The time of contact for chlorination should be at least
A. 5 minutes
B. 20 minutes
C. 1 hour
D. 2 hours
Answer: B. 20 minutes
127. A sewer which receives discharge of a number of house sewers is called a
A. common sewer
B. trunk sewer
C. lateral sewer
D. branch sewer
Answer: C. lateral sewer
128. The artesian spring has too much hydraulic gradient and water flows out automatically.
A. Right
B. Wrong
Answer: A. Right
129. The slow sand filter should be cleaned if the loss of head becomes more than
A. 0.75 m
B. 1.2 m
C. 2.2 m
D. 3.5 m
Answer: B. 1.2 m
130. The self cleaning velocity, recommended for Indian conditions, in order to prevent settling down of seqage at the bottom or on the sides of a large sewer is
A. 0.25 m/s
B. 0.50 m/s
C. 0.75 m/s
D. 1.5 m/s
Answer: C. 0.75 m/s
131. The ground water is generally free from
A. suspended
B. dissolved
Answer: A. suspended
132. The amount of oxygen required for the biological decomposition of dissovled organic solids to occur under aerobic conditions is called bio-chemical oxygen demand (B.O.D.)
A. Correct
B. Incorrect
Answer: A. Correct
133. Sodium carbonate causes
A. hardness
B. softness
Answer: B. softness
134. The yield of the well is measured in
A. cum / h
B. litres / h
C. either (a) or (b)
D. none of these
Answer: C. either (a) or (b)
135. In the freshly produced sewage, aerobic activity is maximum.
A. True
B. False
Answer: A. True
136. Turbidity is the measure of resistance to the passage of
A. light
B. air
Answer: A. light
137. The yield of the well dpends upon the
A. permeability of the soil
B. position of water table
C. depth of well in impervious layer
D. all of these
Answer: D. all of these
138. The layers such as sand and gravel which allow the water to pass through them are known as
A. previous layers
B. aquifers
C. water bearing strata
D. all of these
Answer: D. all of these
139. The presence of bacteria in water causes
A. hardness
B. alkalinity
C. diseases
D. bad taste
Answer: C. diseases
140. Which of the following statement is correct?
A. If the pH value of water is equal to 7, the water is said to be neutral.
B. The pH value determines the strength of the acid or slkali in water.
C. The pH value of water can be obtained by a potentiometer
D. all of the above
Answer: D. all of the above
141. Alkalinity is caused by positively charged hydrogen ions.
A. Right
B. Wrong
Answer: B. Wrong
142. A drop manhole is provided if
A. a sewer drops from a height
B. a branch sewer discharges into the main sewer at a higher level
C. both (a) and (b)
D. none of these
Answer: B. a branch sewer discharges into the main sewer at a higher level
143. A reflux valve, in water distribution system, is used to
A. protect the pipe against negative pressure
B. regulate the flow of water through the pipe
C. prevent water to flow back in the opposite direction
D. all of the above
Answer: C. prevent water to flow back in the opposite direction
144. For an area developed in haphazard way, the type of layout used for the distribution of pipes is known as
A. dead end system
B. ring system
C. radial system
D. grid iron system
Answer: A. dead end system
145. The apparatus used for feeding chlorine into water is called
A. chlorine tank
B. aeration fountain
C. chlorinator
D. none of these
Answer: C. chlorinator
146. For the sewers of diameter less than 600 mm, the type of joint preferred is
A. spigot and socket joint
B. collar joint
C. bandage joint
D. mechanical joint
Answer: A. spigot and socket joint
147. The layers such as lime stone and snd store which do not allow the water to pass through them are known as
A. aquifers
B. aquiclude
C. aquifuge
D. none of these
Answer: B. aquiclude
148. When lead is present in water, it
A. changes its colour
B. causes turbidity
C. causes alkalinity
D. none of these
Answer: D. none of these
149. For the sewers of diameter more than 600 mm, the type of joint preferred is
A. spigot and socket joint
B. collar joint
C. bandage joint
D. mechanical joint
Answer: B. collar joint
150. The odour of water does not change with the temperature.
A. Agree
B. Disagree
Answer: B. Disagree
151. A sluice valve, in water distribution system, is used to
A. protect the pipe against negative pressure
B. regulate the flow of water through the pipe
C. prevent water to flow back in the opposite direction
D. all of tha above
Answer: B. regulate the flow of water through the pipe
152. Plain chlorination is adopted for treating the water having turbidities less than 20 to 30 ppm.
A. Correct
B. Incorrect
Answer: A. Correct
153. The formula, F = R – K (1.8 T + 32), for obtaining the annual run-off is known as
A. Justin’s formula
B. Vermule’s formula
C. Inglis formula
D. Khosla’s formula
Answer: D. Khosla’s formula
154. The product of H+ ions and OH- ions in a water solution is equal to
A. 0
B. 10?1
C. 10?7
D. 10?14
Answer: D. 10?14
155. The water supplysystem should be designed for the present population only.
A. Agree
B. Disagree
Answer: B. Disagree
156. Dissolved impurities consist of
A. bacteria
B. iron
C. slit
D. fungi
Answer: B. iron
157. Water is forced at a preseure higher than the atmospheric pressure in rapid gravity filters.
A. Right
B. Wrong
Answer: B. Wrong
158. Plain sedimentation is a process of retaining water in a basin so that the suspended particles settles down as a result of the
A. action of sun-rays
B. action of gravity and forces
C. action of velocity of the particles
D. none of these
Answer: B. action of gravity and forces
159. The pipe through which liquid waste carrying human excreta flows, is called
A. waste pipe
B. soil pipe
C. vent pipe
D. all of these
Answer: B. soil pipe
160. Which of the following formula is used for computing the quantity of water for fire demand?
A. Freeman’s formula
B. Kuichling formula
C. Buston’s formula
D. all of these
Answer: D. all of these
161. The finely divided dispersion of solid particles which are not visible to the naked eye and cannot be removed by ordinary filters are known as
A. suspended impurities
B. dissolved impurities
C. colloidal impurities
D. none of these
Answer: C. colloidal impurities
162. Rate of filteration of a slow sand filter ranges from
A. 10 to 100 litres / h / m2
B. 100 to 200 litres / h / m2
C. 200 to 400 litres / h / m2
D. 400 to 1000 litres / h / m2
Answer: B. 100 to 200 litres / h / m2
163. For large sewers, the maximum distance between manholes should be
A. 75 m
B. 150 m
C. 200 m
D. 300 m
Answer: D. 300 m
164. The velocity of flow in any sedimentation tank should not exceed
A. 0.05 mm/s
B. 0.5 mm/s
C. 5 mm/s
D. 50 mm/s
Answer: C. 5 mm/s
165. Which of the following statement is correct?
A. The rate of silting in a reservoir is more in the beginning and less in the end.
B. At the economical height of a dam, its cost per million cubic metre of storage is minimum.
C. The percentage of water required for public use amounts to about 10% of the total water requirements.
D. all of the above
Answer: D. all of the above
166. An arrangement for back washing is provided in
A. slow sand filter
B. sedimentation tank
C. rapid sand filter
D. all of these
Answer: C. rapid sand filter
167. The seqage is treated by aerobic bacteria action in
A. settling tank
B. crickling filter
C. oxidation pond
D. all of these
Answer: C. oxidation pond
168. Ventilation of house drainage is required to
A. relieve the pressure of foul gases
B. dilute the fould air in the drain
C. reduce the obnoxious effect of foul air
D. all of these
Answer: D. all of these
169. By base exchange method, water of zero degree hardness can be obtained.
A. Yes
B. No
Answer: A. Yes
170. The alkalinity in water is caused by
A. sodium carbonate
B. potassium carbonate
C. calcium hydroxide
D. all of these
Answer: D. all of these
171. The quantity of liquid waste which flows in sewers during rainy season is called
A. storm sewage
B. dry weather flow
C. sanitary sewage
D. industrial waste
Answer: A. storm sewage
172. Cleaning period for a rapid sand filter is taken as
A. 2 to 3 hours
B. 2 to 3 days
C. 2 to 3 weeks
D. 2 to 3 months
Answer: B. 2 to 3 days
173. The activated sludge
A. contains fertilising constituents
B. indicates the degree of aeration
C. indicates high water content
D. all of these
Answer: D. all of these
174. Lead should be present in large quantity in water.
A. Yes
B. No
Answer: B. No
175. The water obtained from a lake is known as surface water.
A. Agree
B. Disagree
Answer: A. Agree
176. The most commonly used disinfectant for drinking water throughout the world is
A. alum
B. nitorgen
C. lime
D. chlorine
Answer: D. chlorine
177. In high rate activated sludge treatment, bacterias are removed from
A. 20 to 40%
B. 40 to 60%
C. 60 to 80%
D. 80 to 95%
Answer: D. 80 to 95%
178. The water mains should be designed for
A. 100%
B. 150%
C. 225%
D. 250%
Answer: C. 225%
179. Pressure filters are not used for treating municipal water supplies, because
A. the rate of filteration is high
B. the overall plant capacity is small
C. they are inefficient in the removal of turbidity and bacterias
D. they are more costly
Answer: D. they are more costly
180. The process of killing pathogenic bacterias from water is called
A. sedimentation
B. filteration
C. coagulation
D. disinfection
Answer: D. disinfection
181. Bacterias which cause disease are called
A. anaerobic bacteria
B. facultative bacterias
C. aerobic bacteria
D. none of these
Answer: D. none of these
182. The sewage should be disposed off without causing odour and nuisance.
A. Right
B. Wrong
Answer: A. Right
183. The permanent hardness in water is caused due to the salts like
A. chlorides
B. nitrates
C. sulphates
D. all of these
Answer: D. all of these
184. The sodium carbonate in water
A. causes bad taste
B. softens the water
C. increases hardness of water
D. stops epidemic
Answer: B. softens the water
185. An artesian spring is formed
A. when an aquifer gets exposed in a valley against a vertical cut
B. due to continuous fault in a rock through which water under pressure comes out
C. when a porous strata gets enclosed between two impervious strata
D. none of the above
Answer: C. when a porous strata gets enclosed between two impervious strata
186. If the size of the sewer is small, then the velocity of flow will be high.
A. Yes
B. No
Answer: B. No
187. Slow sand filter is efficient to remove the bacterias from the raw water to an extent of
A. 50%
B. 70%
C. 85%
D. 99%
Answer: D. 99%
188. The bacteria which can survive without oxygen is called
A. anaerobic bacteria
B. pathogenic bacteria
C. aerobic bacteria
D. non-pathogenic bacteria
Answer: A. anaerobic bacteria
189. For large cities, the suitable method for forecasting population is
A. arithmetical increase method
B. graphical method
C. geometrical increase method
D. comparative method
Answer: A. arithmetical increase method
190. When the sewage is to be distributed over a level area surrounded by dykes (i.e. trenches), the mothod of sewage used is called
A. flooding
B. surface irrigation
C. ride and furrow
D. spray irrigation
Answer: A. flooding
191. In order to control the flow of water through pipes, a
A. scour valve
B. air valve
C. gate valve
D. safety valve
Answer: C. gate valve
192. The underground structure in the form of a circular or rectangular tank for the purposes of admitting sewage into it from the intercepting chamber is called a
A. septic tank
B. cess pool
C. privy pit
D. soak pit
Answer: B. cess pool
193. A sewer which gets discharge from two or more main sewers is called
A. main sewer
B. trunk sewer
C. combined sewer
D. intercepting sewer
Answer: B. trunk sewer
194. Zeolite is
A. hydrated silica
B. sodium silicate
C. dehydrated calcium silicate
D. none of these
Answer: B. sodium silicate
195. In orthotolodine test, safe residual for drinking water is indicated by
A. yellow colour
B. green colour
C. lemon yellow colour
D. none of these
Answer: A. yellow colour
196. The secondary treatment of sewage is carried out by the use of
A. screens
B. grit chambers
C. trickling filters
D. chlorinators
Answer: C. trickling filters
197. According to Indian standards, 45 litres of water per person per day is provided in case of
A. hotels
B. hostels
C. offices
D. all of these
Answer: C. offices
198. The plain ends of cast iron pipes are joined by
A. spigot and socket joint
B. flanged joint
C. victuallic joint
D. dresser coupling joint
Answer: D. dresser coupling joint
199. Pressure filters are best suited for
A. swimming pools
B. railway stations
C. individual industries
D. all of these
Answer: D. all of these
200. A pressure relief valve is provided to prevent
A. the water flowing out of the suction pipe
B. the back flow, when the pump is stopped
C. the increase of pressure after certain safe limit
D. all of the above
Answer: C. the increase of pressure after certain safe limit
201. Aerobic bacterias takes place in the
A. presence
B. absence
Answer: A. presence
202. Sludge treatment is mainly done in order to
A. stablize the organic matter
B. destroy the pathogenic bacterias
C. reduce the water content
D. all of these
Answer: D. all of these
203. The total count of bacteria per cubic centimetre for domestic purposes varies from
A. 0 to 100
B. 100 to 150
C. 150 to 200
D. 200 to 250
Answer: A. 0 to 100
204. The internal diameter of the sewer should not be less than
A. 15 cm
B. 25 cm
C. 50 cm
D. 75 cm
Answer: A. 15 cm
205. The minimum dissolved oxygen required in water to save the aquatic life is
A. 1 ppm
B. 2 ppm
C. 4 ppm
D. 8 ppm
Answer: C. 4 ppm
206. Which of the following statement is wrong?
A. For land disposal, large areas with preferably sandy types of soil are required.
B. The land disposal requires either preliminary or primary treatment of sewage.
C. The land disposal saves the inland stream from getting polluted by sewage.
D. none of the above
Answer: D. none of the above
207. B-coli or E-coli are harmless organisms but their presence in water indicates the
A. presence of pathogenic bacteria
B. absence of pathogenic bacteria
C. presence of non-pathogenic bacteria
D. absence of non-pathogenic bacteria
Answer: A. presence of pathogenic bacteria
208. In combined system, automatic flushing is not possible.
A. Correct
B. Incorrect
Answer: B. Incorrect
209. The copper contents in water for domestic purposes should not be
A. less than
B. more than
Answer: B. more than
210. The maximum permissible quantity of iron and manganese in water for domestic purposes should be
A. 0.1 ppm
B. 0.3 ppm
C. 0.6 ppm
D. 0.8 ppm
Answer: B. 0.3 ppm
211. The maximum permissible fluorine content in water for domestic supplies should be
A. 0.15 ppm
B. 1.5 ppm
C. 15 ppm
D. 150 ppm
Answer: B. 1.5 ppm
212. When high level spots are not available for the construction of ground level reservoirs, elevated reservoirs can be used.
A. Agree
B. Disagree
Answer: A. Agree
213. The capacity of the pumps is normally expressed as
A. litres per minute
B. cubic metres per day
C. thousands of litres per hour
D. all of these
Answer: D. all of these
214. In presure filters, water is forced at a pressure
A. equal to
B. less than
C. greater than
Answer: C. greater than
215. No deposition will take place in
A. larger
B. smaller
Answer: B. smaller
216. The volume of a settling basin is large due to
A. large volumes of floc added for coagulation
B. large amount of water entrapped into it
C. greater amount of suspended solids to be removed
D. none of the above
Answer: D. none of the above
217. The main object of sewage disposal is
A. to dispose off properly human excreta to a safe place before its creates unhealthy conditions in the locality
B. to dispose off waste water from an area so that it may not become breeding place for mosquitoes
C. to dispose off the sewage after giving it treatment so that the receiving land may not get polluted
D. all of the above
Answer: D. all of the above
218. For building drainage pipes, a smoke test is applied.
A. Correct
B. Incorrect
Answer: A. Correct
219. The maximum permissible colour for domestic supplies, on platinum cobalt scale is
A. 5 to 10 ppm
B. 10 to 20 ppm
C. 20 to 30 ppm
D. 30 to 40 ppm
Answer: B. 10 to 20 ppm
220. The maximum permissible turbidity for domestic supplies, on silica scale is
A. 5 to 10 ppm
B. 10 to 20 ppm
C. 20 to 30 ppm
D. 30 to 40 ppm
Answer: A. 5 to 10 ppm
221. The rate of settling of a particle in water depends upon the
A. viscosity of water
B. density of water
C. specific gravity of particle
D. all of these
Answer: D. all of these
222. The quantity of water available from an infiltration gallery depends upon the
A. size of gallery
B. nature of soil
C. yield of source
D. all of these
Answer: D. all of these
223. The treatment which employs mechanical and hydraulic separation principles is referred as secondary treatment.
A. Yes
B. No
Answer: B. No
224. A good trap should
A. not have self cleaning property
B. restrict the flow of water
C. provide an adequate water seal at all times
D. all of these
Answer: C. provide an adequate water seal at all times
225. The organic impurities in water form a layer on the top of a filtering media. Such a layer is called
A. permeable layer
B. filtering layer
C. dirty skin
D. none of these
Answer: C. dirty skin
226. In one pipe system of plumbing, waste water is carried away from
A. bath rooms
B. kitchens
C. wash basins
D. all of these
Answer: D. all of these
227. In designing a water works for a city to meet the water demand for public use, a provision of about
A. 5%
B. 10%
C. 20%
D. 25%
Answer: B. 10%
228. A pipe used to carry discharge from sanitary fittings like bathrooms, kitchens etc, is called
A. waste pipe
B. soil pipe
C. vent pipe
D. anti-siphonage pipe
Answer: A. waste pipe
229. When the pH value of water is
A. equal to 7
B. less than 7
C. more than 7
Answer: B. less than 7
230. The equipment used for checking the levels of the sewer inverts is
A. dumpy level
B. theodolite
C. boning rod
D. all of these
Answer: C. boning rod
231. The pH value of water for public supplies is limited from
A. 2.5 to 6.5
B. 6.5 to 8
C. 8 to 10.5
D. 10.5 to 15
Answer: B. 6.5 to 8
232. The yield of a underground source may be obtained by
A. pumping test
B. recupating test
C. both (a) and (b)
D. none of these
Answer: C. both (a) and (b)
233. The coefficient of uniformity for rapid sand filters is
A. more
B. less
Answer: B. less
234. For house drainage and lateral connections, we shall use
A. stone ware sewers
B. cast iron sewers
C. concrete sewers
D. masonry sewers
Answer: A. stone ware sewers
235. The cross-section recommended for separate system of sewerage is
A. circular
B. egg-shaped
C. rectangular
D. none of these
Answer: C. rectangular
236. In the design of a sedimentation tank, the essential factor to be considered is
A. period of detention
B. sludge capacity
C. velocity of flow
D. all of these
Answer: D. all of these
237. House plumbing is difficult in
A. separate
B. combined
Answer: A. separate
238. pH value is a symbol for
A. magnesium
B. hydrogen
C. calcium
D. sodium
Answer: B. hydrogen
239. The quantity of arsenic in water for domestic purposes should not be more than 0.05 ppm.
A. True
B. False
Answer: A. True
240. After cleaning the slow sand filter, the filtered water should not be used for a period of
A. upto 6 hours
B. 6 hours to 12 hours
C. 12 hours to 24 hours
D. 24 hours to 48 hours
Answer: D. 24 hours to 48 hours
241. By lime soda process, hardness can be reduced to less than
A. 50 ppm
B. 75 ppm
C. 100 ppm
D. 150 ppm
Answer: A. 50 ppm
242. In pre-chlorination, the raw water is treated with chlorine only.
A. Agree
B. Disagree
Answer: B. Disagree
243. Aluminium sulphate may be used for coagulation.
A. Correct
B. Incorrect
Answer: A. Correct
244. Disposal by dilution will be suitable where
A. there are strong forward currents
B. there is no back currents
C. the sewage arriving at the out fall point is fresh and non-septic
D. all of the above
Answer: D. all of the above
245. Cleaning period for a slow sand filter is taken as
A. 1 hour to 3 hours
B. 1 day to 3 days
C. 1 week to 3 weeks
D. 1 month to 3 months
Answer: D. 1 month to 3 months
246. The open wells or dug wells wells
A. act as a small storage reservoir
B. are suitable for a small discharge
C. are cheap in construction
D. all of these
Answer: D. all of these
247. In Zeolite process
A. no sludge is formed
B. water of varying quality can be treated
C. ferrous and manganese from water are removed
D. all of tha above
Answer: D. all of tha above
248. Hard water may cause bursting of boilers.
A. Agree
B. Disagree
Answer: A. Agree
249. The amount of water collected in a reservoir is divided into three portions and the order of their existance from bottom to the top is
A. useful storage, surcharge storage, dead storage
B. useful storage, dead storage, surcharge storage
C. dead storage, useful storage, surcharge storage
D. none of the above
Answer: C. dead storage, useful storage, surcharge storage
250. The permanent hardness of water can be removed by
A. adding alum
B. adding chlorine
C. boiling
D. zeolite process
Answer: D. zeolite process
251. Coagulation is required when the particles are of
A. fine
B. coarse
Answer: A. fine
252. A sewer which receives sewage from the collection system and conducts it to a point of final disposal is called a
A. common sewer
B. trunk sewer
C. branch sewer
D. outfall sewer
Answer: D. outfall sewer
253. The effective size of sand particles for rapid sand filters varies from
A. 0.30 to 0.35 mm
B. 0.35 to 0.50 mm
C. 0.50 to 0.65 mm
D. 0.65 to 0.75 mm
Answer: B. 0.35 to 0.50 mm
254. Which of the following statement is correct?
A. Sewage, if not treated, will create healthy conditions.
B. Secondary treatment of sewage works on hydraulic separation principle.
C. Primary clarifiers are to the sedimentation tanks located just after the girt chambers.
D. Trickling filter is different from percolating filter.
Answer: C. Primary clarifiers are to the sedimentation tanks located just after the girt chambers.
255. In India, as per Indian standards, water consumption per capita per day for domestic purpose is
A. 85 litres
B. 100 litres
C. 115 litres
D. 135 litres
Answer: D. 135 litres
256. Bacteria which can survive with or without free oxygen is known as facultative bacteria.
A. Correct
B. Incorrect
Answer: A. Correct
257. The minimum size of a fire hydrant is
A. 5 cm
B. 10 cm
C. 15 cm
D. 20 cm
Answer: C. 15 cm
258. The treatment of water with only chlorine is known as
A. plain chlorination
B. post cholorination
C. pre-chlorination
D. de-chlorination
Answer: A. plain chlorination
259. The under drainage system in a rapid sand filters
A. receives and collects the filtered water
B. allows back washing for cleaning the filter
C. both (a) and (b)
D. none of these
Answer: C. both (a) and (b)
260. The under drainage system in slow sand filters
A. receives and collects the filtered water
B. allows back washing for cleaning the filter
C. both (a) and (b)
D. none of these
Answer: A. receives and collects the filtered water
261. The storm sewers are essentially required to
A. avoid creation of unfavourable healthy conditions
B. improve the general appearance of the city
C. dispose off the first washings of early showers as quickly as possible
D. all of the above
Answer: D. all of the above
262. In a rapid sand filter
A. raw water from the source is supplied
B. disinfected raw water is supplied
C. raw water passed through coagulation tank is supplied
D. any one of the above
Answer: C. raw water passed through coagulation tank is supplied
263. In primary settling tank, suspended solids are reduced from
A. 10 to 20%
B. 20 to 40%
C. 40 to 70%
D. 70 to 90%
Answer: C. 40 to 70%
264. The domestic use of water amounts to
A. 20%
B. 30%
C. 40%
D. 50%
Answer: D. 50%
265. A combined system will be favourable when
A. the sewers are to be laid in rocks
B. the finances are limited
C. the topography is flat necessitating deep excavation for combined sewers
D. the locality to be served has narrow streets
Answer: D. the locality to be served has narrow streets
266. The presence of carbon dioxide in water causes acidity.
A. True
B. False
Answer: A. True
267. The maximum permissible temperature for domestic supply is
A. 5 to 10?C
B. 10 to 15?C
C. 15 to 20?C
D. 20 to 25?C
Answer: B. 10 to 15?C
268. Which of the following is not a coagulating agent?
A. Ferric sulphate
B. Ferric chloride
C. Aluminium sulphate
D. Copper sulphate
Answer: D. Copper sulphate
269. The bio-chemical treatment of sewage effluent is a process of
A. oxidation
B. deoxidation
C. self purification
D. sedimentation
Answer: A. oxidation
270. The design period for a water supply project is taken as
A. 5 to 10 years
B. 10 to 15 years
C. 15 to 20 years
D. 20 to 30 years
Answer: D. 20 to 30 years
271. Which of the following statement is correct?
A. Pre-chlorination reduces the bacterial load on filters.
B. The substance used for disinfection of water is known as coagulant.
C. Chlorine cannot be applied in the form of chloramines.
D. all of the above
Answer: A. Pre-chlorination reduces the bacterial load on filters.
272. The bacterias which do not cause any disease are called pathogenic bacterias.
A. Right
B. Wrong
Answer: B. Wrong
273. In order to prevent water to flow back in opposite direction, we shall use a
A. scour valve
B. air valve
C. gate valve
D. reflux valve
Answer: D. reflux valve
274. A reflux valve is also known as
A. safety valve
B. scour valve
C. air valve
D. check valve
Answer: D. check valve
275. The effluents from the septic tank are discharged into
A. soak pit
B. drainage
C. oxidation pond
D. sewer
Answer: A. soak pit
276. Which of the following statement is wrong?
A. The water closets should be such that excreta do not stick to it
B. The trap prevents the entry of foul gases.
C. The trap should have self cleaning velocity
D. The water closet is provided for receiving garbage.
Answer: D. The water closet is provided for receiving garbage.
277. Zeolite process is also known as
A. base exchange process
B. Cation exchange process
C. both (a) and (b)
D. none of these
Answer: C. both (a) and (b)
278. The privy pit should be located at least
A. 3 m
B. 10 m
C. 30 m
D. 50 m
Answer: A. 3 m
279. The most common coagulant is
A. magnesium sulphate
B. alum
C. chlorine
D. bleaching powder
Answer: B. alum
280. A pipe conveying sewage from the plumbing system of a singe building to a common sewer or to the point of immediate disposal is called
A. common sewer
B. house sewer
C. lateral sewer
D. outfall sewer
Answer: B. house sewer
281. The process of adding certain chemicals to water in order to form flocculent precipitate for absorbing and entraining colloidal mater is called sedimentation with coagulation.
A. Agree
B. Disagree
Answer: A. Agree
282. The particle will settle down more rapidly in water at high temperatures than at lower temperatures.
A. True
B. False
Answer: A. True
283. For a well planned city, we whall use the grid iron system for the distribution of pipes.
A. Right
B. Wrong
Answer: A. Right
284. Which of the following statement is wrong?
A. A check valve is provided on the delivery side in between the pump and the gate valve.
B. A pressure relief and air valve are provided on the delivery side.
C. Scour valves are provided at high points
D. all of the above
Answer: C. Scour valves are provided at high points
285. In a plain sedimentation tank, under normal conditions, impurities are removed upto
A. 50%
B. 60%
C. 70%
D. 80%
Answer: C. 70%
286. The colour of water is expressed in numbers of a
A. silica scale
B. platinum cobalt scale
C. pO value
D. none of these
Answer: B. platinum cobalt scale
287. Cess pool is not recommended by the health authorities.
A. Agree
B. Disagree
Answer: A. Agree
288. The percentage of chlorine in fresh bleaching powder is
A. 20 to 25%
B. 25 to 30%
C. 30 to 35%
D. 35 to 40%
Answer: C. 30 to 35%
289. The amount of chlorine used for plain chlorination of water is about
A. 0.2 ppm
B. 0.3 ppm
C. 0.4 ppm
D. 0.5 ppm
Answer: D. 0.5 ppm
290. The maximum acidity in water will occur at a pH value of
A. 0
B. 2
C. 7
D. 14
Answer: A. 0
291. The corrosion in pipe is due to
A. dissolved oxygen in water
B. pH value of water
C. impurities in the material particularly those having a lower potential
D. all of the above
Answer: D. all of the above
292. The method in which different types of refuse are collected, carried and disposed off separately is called
A. conservancy method
B. dry method
C. water carriage method
D. either (a) and (b)
Answer: D. either (a) and (b)
293. Membrane filter technique is used for testing
A. E-coli
B. copper
C. pathogenic bacterias
D. none of these
Answer: A. E-coli
294. The commercial osmoscope is graduated with pO values from
A. 0 to 5
B. 5 to 10
C. 10 to 15
D. 15 to 20
Answer: A. 0 to 5
295. The sanitation system in which a small portion of storm water is allowed to enter in the sanitary sewage sewers and the remaining storm water flows in separate set of sewers, is known as
A. separate system
B. combined system
C. partially separate system
D. partially combined system
Answer: C. partially separate system
296. The effective size of sand particles for slow sand filters varies from
A. 0.30 to 0.35 mm
B. 0.35 to 0.50 mm
C. 0.50 to 0.65 mm
D. 0.65 to 0.75 mm
Answer: A. 0.30 to 0.35 mm
297. The process of purifying water by passing it through a bed of fine granular material, is called
A. screening
B. filteration
C. coagulation
D. sedimentation
Answer: B. filteration
298. In one pipe system of plumbing,
A. only one pipe is provided
B. the main pipe is connected directly to the drainage system
C. all of the traps are fully ventilated and connected to the ventilation pipe
D. all of the above
Answer: D. all of the above
299. The water of a river has an important property called
A. turbidity
B. self purification
C. permeability
D. infiltration capacity
Answer: B. self purification
300. Suspended impurities include
A. algae
B. protozoa
C. fungi
D. all of these
Answer: D. all of these
301. The anti-siphonage pipe is not required in
A. one pipe system
B. two pipe system
C. single stack system
D. none of these
Answer: C. single stack system
302. In dry feeding type of coagulants, the dose of coagulant is controlled by
A. scrapers
B. worm wheel
C. paddles
D. none of these
Answer: B. worm wheel
303. The open wells or dug wells are also known as
A. shallow wells
B. draw wells
C. percolation wells
D. all of these
Answer: D. all of these
304. The maximum permissible quantity of lead in water for domestic supplies is
A. 0.01 ppm
B. 0.05 ppm
C. 0.50 ppm
D. 1 ppm
Answer: B. 0.05 ppm
305. The ideal method of disinfection of swimming pool water is by
A. chlorination
B. lime treatment
C. ozonisation
D. ultra-violet rays
Answer: C. ozonisation
306. A pipe sunk into the ground to tap the underground water is called
A. open well
B. tube well
C. artesian well
D. infiltration well
Answer: B. tube well
307. The method adopted for removing, bushes branches, debries etc. from water is known as
A. sedimentation
B. coagulation
C. screening
D. filteration
Answer: C. screening
308. The water carriage sewage system removes
A. domestic sewage
B. industrial sewage
C. storm sewage
D. all of these
Answer: D. all of these
309. Colloidal impurities if associated with organic matter having bacterias becomes the chief source of
A. hardness
B. epidemic
C. alkalinity
D. bad taste
Answer: B. epidemic
310. The quantity of storm water (Q) in liter per second is given by Q = CA3/4. This formula is called
A. Fanning’s formula
B. Ryve’s formula
C. Dicken’s formula
D. Inglis formula
Answer: C. Dicken’s formula
311. The leakage of sewage from the sewer into the soil surrounding the water is called ex-filtration.
A. Agree
B. Disagree
Answer: A. Agree
312. Which of the following statement is correct?
A. The sub-surface sources are not affected by draught.
B. Infiltration galleries are most suitable for increasing the surface source supply, in dry season.
C. The rate at which water percolates into well under safe maximum critical depression head is called yield of well.
D. all of the above
Answer: D. all of the above
313. The percentage ratio of the oxygen available in sewage to the oxygen required to satisfy one stage of bio-chemical oxygen demand (B.O.D.) is termed as
A. chemical oxygen demand
B. oxygen consumed
C. relative stability
D. bio-oxygen demand
Answer: C. relative stability
314. The continuous flow of water may be expected from
A. surface springs
B. artesian springs
C. gravity springs
D. all of these
Answer: B. artesian springs
315. The void spaces in the filtering material act like a
A. drain
B. inlet
C. tiny settling basins
D. outlet
Answer: C. tiny settling basins
316. Residual chlorine in water is determined by
A. versenate
B. starch-iodide
Answer: B. starch-iodide
317. Rpid sand filters are suitable for small towns and villages.
A. Yes
B. No
Answer: B. No
318. The prsence of sodium chloride in water
A. causes bad taste
B. softens the water
C. increases hardness of water
D. stops epidemic
Answer: B. softens the water
319. A scour valve, in a water distribution system, is provided at
A. low points
B. high points
C. junction points
D. all of these
Answer: A. low points
320. The growth of population may be conveniently represented by
A. semi-logarthmic curve
B. logistic curve
C. straight line curve
D. all of these
Answer: B. logistic curve
321. The earth’s water circulatory system is known as.
A. water cycle
B. hydrological cycle
C. precipitation cycle
D. all of these
Answer: B. hydrological cycle
322. The odour of water can be determined by
A. thermometer
B. Osmoscope
C. Jackson’s turbidimeter
D. none of these
Answer: B. Osmoscope
323. Grit should be removed from sewage before
A. their disposal in dilution water
B. their lifting by means of pump etc.
C. settling of sewage in sedimentation tank
D. all of the above
Answer: D. all of the above
324. When a pervious strata is sandwitched between two impervious strata of cup shape, the well is called a tube well.
A. True
B. False
Answer: B. False
325. If the level of source of water is higher than that of the place of consumption, the system adopted for supplying water is
A. pumping system
B. gravitational system
C. combined pumping and gravity system
D. any one of these
Answer: B. gravitational system
326. The residual chlorine
A. is zero
B. is maximum
C. reappears
Answer: C. reappears