1. The main function of centrifugal pumps are to ________.
A. Transfer speed.
B. Transfer pressure.
C. Transfer temperature.
D. Transfer energy.
Answer = Transfer energy
2. The pump injects compressed air at the _________.
A. Rotor pipe.
B. Bottom of the discharge pipe.
C. Top of the discharge pipe.
D. Rotor to draft.
Answer = Bottom of the discharge pipe
3. Which among the following control the flow rate?.
A. Valve.
B. Pump.
C. Head.
D. Tank pipe.
Answer = Valve
4. The compressed air mixes with the liquid casing to become less dense..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer = TRUE
5. The inlet passage of water entry is controlled by ________.
A. Head race.
B. Gate.
C. Tail race.
D. Pump.
Answer = Gate
6. Airlift pumps are widely used in aquaculture to pump..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer = TRUE
7. Centrifugal pumps are used to transport ________.
A. Pressure.
B. Speed.
C. Power.
D. Fluid.
Answer = Fluid
8. The air lift pump works under the principle of _______.
A. Newtons equation.
B. Buoyancy.
C. Momentum conservation.
D. Hydrodynamic energy.
Answer = Buoyancy
9. With the increase in load, Energy in the turbine________.
A. Decreases.
B. Increases.
C. Remains same.
D. Independent.
Answer = Decreases
10. The rotational kinetic energy comes from ______.
A. Engine motor.
B. Pump.
C. Tank.
D. Draft tube.
Answer = Engine motor
11. When the balancing of the turbine is disturbed, we use ________.
A. Throttle governing.
B. Steam governing.
C. Nozzle governing.
D. Emergency governing.
Answer = Emergency governing
12. The fluid coming into the airlift pump is accelerated by ________.
A. Throttle.
B. Impeller.
C. Nozzle.
D. Governor.
Answer = Impeller
13. A gear pump uses ___________.
A. Petrochemical pumps.
B. Meshing of gears.
C. Froth pumps.
D. Airlift pumps.
Answer = Meshing of gears
14. A pump that has low suction and moderate discharge of liquid is called ________.
A. Airlift Pump.
B. Vacuum pump.
C. Turbine pump.
D. Draft tube.
Answer = Airlift Pump
15. The most common pump used for hydraulic fluid power application is __________.
A. Centrifugal pumps.
B. Gear pump.
C. Froth pumps.
D. Airlift pumps.
Answer = Gear pump
16. The main function of gear pumps are to ________.
A. Transfer speed.
B. Transfer pressure.
C. Transfer temperature.
D. Transfer energy.
Answer = Transfer energy
17. Centrifugal pumps transfer energy from _______.
A. Rotor to fluid.
B. Fluid to rotor.
C. Draft to rotor.
D. Rotor to draft.
Answer = Rotor to fluid
18. Gear pumps are mainly used in chemical installations because they pump ________.
A. High viscosity fluids.
B. High density fluids.
C. High pressure fluids.
D. High temperature fluids.
Answer = High viscosity fluids
19. Gear pumps convert rotational kinetic energy to hydrodynamic energy..
A. TRUE.
B. FALSE.
C. Nothing can be said.
D. None of the mentioned.
Answer = TRUE
20. The injection pumps used in most diesel engines can create up to ________.
A. 300 psi.
B. 3000 psi.
C. 30000 psi.
D. 3 psi.
Answer = 30000 psi
21. A pneumatic sewage ejector includes a tank for holding _________.
A. Fluid sewage.
B. Horizontally sewage.
C. Axial sewage.
D. Radial sewage.
Answer = Fluid sewage
22. Gear pumps are used to transport ________.
A. Pressure.
B. Speed.
C. Power.
D. Fluid.
Answer = Fluid
23. Centrifugal pumps transport fluids by converting _________.
A. Kinetic energy to hydrodynamic energy.
B. Hydrodynamic energy to kinetic energy.
C. Mechanical energy to kinetic energy.
D. Mechanical energy to Hydrodynamic energy.
Answer = Kinetic energy to hydrodynamic energy
24. With the increase in load, Energy in the turbine ________.
A. Decreases.
B. Increases.
C. Remains same.
D. Independent.
Answer = Decreases
25. The rotational kinetic energy comes from ______.
A. Engine motor.
B. Pump.
C. Tank.
D. Draft tube.
Answer = Engine motor
26. When the balancing of the turbine is disturbed, we use ________.
A. Throttle governing.
B. Steam governing.
C. Nozzle governing.
D. Emergency governing.
Answer = Emergency governing
27. Gear pumps are ___________.
A. Tangential flow pumps.
B. Positive displacement pumps.
C. Negative displacement pumps.
D. Radial pumps.
Answer = Tangential flow pumps
28. The hourly variation factor is usually taken as______________?.
A. 1.5
B. 1.8
C. 2.0
D. 2.7.
Answer = 1.5
29. The distribution mains are designed for________________?.
A. maximum daily demand
B. maximum hourly demand
C. average daily demand
D. maximum hourly demand on maxi¬mum day.
Answer = maximum hourly demand on maxi¬mum day
30. The depression of water table in a well due to pumping will be maximum_______________?.
A. at a distance R from the well
B. close to the well
C. at a distance R/2 from the well
D. none of the above where R is the radius of influence.
Answer = close to the well
31. The type of valve, which is provided on the suction pipe in a tube-well, is____________?.
A. air relief valve
B. reflux valve
C. pressure relief valve
D. sluice valve.
Answer = reflux valve
32. As compared to shallow-wells, deep wells have______________?.
A. more depth
B. less depth
C. more discharge
D. less discharge.
Answer = more discharge
33. The polluted water is one which_______________?.
A. contains pathogenic bacteria
B. consists of undesirable substances rendering it unfit for drinking and domestic use
C. is safe and suitable for drinking and domestic use
D. is contaminated.
Answer = consists of undesirable substances rendering it unfit for drinking and domestic use
34. The most common cause of acidity in water is_______________?.
A. carbon dioxide
B. oxygen
C. hydrogen
D. nitrogen.
Answer = carbon dioxide
35. Alkalinity in water is expressed as milli-grams per litre in terms of equivalent_______________?.
A. calcium carbonate
B. magnesium carbonate
C. sodium carbonate
D. calcium hydroxide.
Answer = calcium carbonate
36. The maximum permissible limit for flouride in drinking water is______________?.
A. 0.1 mg/litre
B. 1.5 mg/litre
C. 5 mg/litre
D. 10 mg/litre.
Answer = 1.5 mg/litre
37. Turbidity is measured on_______________?.
A. standard silica scale
B. standard cobalt scale
C. standard platinum scale
D. platinum cobalt scale.
Answer = standard silica scale
38. Residual chlorine in water is determined by________________?.
A. starch iodide method
B. orthotolidine method
C. both (A) and (B)
D. none of the above.
Answer = both (A) and (B)
39. If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to________________?.
A. total alkalinity
B. total hardness
C. total hardness – total alkalinity
D. non carbonate hardness.
Answer = total alkalinity
40. The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?.
A. 1 mg/litre
B. 10 mg/litre
C. 100 mg/litre
D. 1000 mg/litre.
Answer = 10 mg/litre
41. The length of rectangular sedimentation tank should not be more than_______________?.
A. B
B. 2B
C. 4B
D. 8B.
Answer = 4B
42. Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about_______________?.
A. 10 to 25
B. 50
C. 75
D. 100.
Answer = 75
43. The settling velocity of a particle in a sedimentation tank increases if______________?.
A. particle size is decreased
B. the surface area of tank is increased
C. the depth of tank is decreased
D. none of the above.
Answer = none of the above
44. The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally_______________?.
A. less and more
B. less and less
C. more and less
D. more and more.
Answer = more and less
45. Alum as a coagulant is found to be most effective when pH range of water is______________?.
A. 2 to 4
B. 4 to 6
C. 6 to 8
D. 8 to 10.
Answer = 6 to 8
46. The alum, when added as a coagulant in water_______________?.
A. does not require alkalinity in water for flocculation
B. does not affect pH value of water
C. increases pH value of water
D. decreases pH value of water.
Answer = decreases pH value of water
47. In water treatment, rapid gravity filters are adopted to remove_______________?.
A. dissolved organic substances
B. dissolved solids and dissolved gases
C. floating solids and dissolved inorganic solids
D. bacteria and colloidal solids.
Answer = bacteria and colloidal solids
48. The effective size of sand particles used in slow sand filters is_______________?.
A. 0.25 to 0.35 mm
B. 0.35 to 0.60 mm
C. 0.60 to 1.00 mm
D. 1.00 to 1.80 mm.
Answer = 0.25 to 0.35 mm
49. Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below?.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true.
Answer = Both A and R are true and R is the correct explanation of A
50. The percentage of filtered water, which is used for backwashing in rapid sand filters, is about______________?.
A. 0.2 to 0.4
B. 0.4 to 1.0
C. 2 to 4
D. 5 to 7.
Answer = 2 to 4
51. The rate of Alteration of pressure filters is_________________?.
A. less than that of slow sand filters
B. in between the filtration rate of slow sand filters and rapid sand filters
C. greater than that of rapid sand filters
D. equal to that of slow sand filters.
Answer = greater than that of rapid sand filters
52. Chlorine demand of water is equal to________________?.
A. applied chlorine
B. residual chlorine
C. sum of applied and residual chlorine
D. difference of applied and residual chlorine.
Answer = difference of applied and residual chlorine
53. The percentage of chlorine in fresh bleaching powder is about________________?.
A. 10 to 15
B. 20 to 25
C. 30 to 35
D. 40 to 50.
Answer = 30 to 35
54. The suitable method for disinfection of swimming pool water is________________?.
A. ultra violet rays treatment
B. lime treatment
C. by using potassium permanganate
D. chlorination.
Answer = ultra violet rays treatment
55. In chlorination, with the rise in temperature of water, death rate of bacteria____________?.
A. increases
B. decreases
C. remains unaffected
D. none of the above.
Answer = increases
56. The population of a town in three consecutive years are 5000, 7000 and 8400 respectively. The population of the town in the fourth consecutive year according to geometrical increase method is________________?.
A. 9500
B. 9800
C. 10100
D. 10920.
Answer = 10920
57. Disinfection efficiency is________________?.
A. reduced at higher pH value of water
B. unaffected by pH value of water
C. increased at higher pH value of water
D. highest at pH value equal to 7.
Answer = reduced at higher pH value of water
58. The major disadvantage of lime soda process of water softening is that_________________?.
A. it is unsuitable for turbid and acidic water
B. huge amount of precipitate is formed which creates a disposal problem
C. the effluent cannot be reduced to zero hardness
D. it is unsuitable for softening the water of excessive hardness.
Answer = huge amount of precipitate is formed which creates a disposal problem
59. Activated carbon is used for_____________?.
A. disinfection
B. removing hardness
C. removing odours
D. removing corrosiveness.
Answer = removing odours
60. The suitable layout of a distribution system for irregularly growing town is_______________?.
A. dead end system
B. grid iron system
C. radial system
D. ring system.
Answer = dead end system
61. The suitable layout of distribution system for a city with roads of rectangular pattern is______________?.
A. grid iron system
B. dead end system
C. ring system
D. radial system.
Answer = grid iron system
62. The method of analysis of distribution system in which the domestic supply is neglected and fire demand is considered is________________?.
A. circle method
B. equivalent pipe method
C. electrical analysis method
D. Hardy cross method.
Answer = circle method
63. The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is_______________?.
A. check valve
B. sluice valve
C. safety valve
D. scour valve.
Answer = sluice valve
64. Scour valves are provided ______________?.
A. at street corners to control the flow of water
B. at every depression and dead ends to drain out the waste water that may collect there
C. at the foot of rising main along the slope to prevent back running of water
D. at every summit of rising mains.
Answer = at every depression and dead ends to drain out the waste water that may collect there
65. A pipe conveying sewage from plumbing system of a single building to common sewer or point of immediate disposal is called________________?.
A. house sewer
B. lateral sewer
C. main sewer
D. submain sewer.
Answer = house sewer
66. Average rate of water consumption perhead per day as per Indian Standard is______________?.
A. 100 litres
B. 135 litres
C. 165 litres
D. 200 litres.
Answer = 135 litres
67. Which of the following sewers is preferred for combined system of sewage ?.
A. circular sewer
B. egg shaped sewer
C. rectangular sewer
D. none of the above.
Answer = egg shaped sewer
68. The water carriage system of collection of waste product________________?.
A. is cheaper in initial cost than dry conservancy system
B. requires treatment before disposal
C. creates hygenic problem
D. all of the above.
Answer = requires treatment before disposal
69. The time of concentration is defined as_______________?.
A. the time taken by rainfall water to run from most distant point of water shed to the inlet of sewer
B. the time required for flow of water in sewer to the point under consideration
C. sum of (A) and (B)
D. difference of (A) and (B).
Answer = sum of (A) and (B)
70. The self cleansing velocity for all sewers in India is usually_________________?.
A. less than 1.0 m/sec
B. 1.0 m/sec to 1.2 m/sec
C. 1.5 m/sec to 2.0 m/sec
D. 3.0 m/sec to 3.5 m/sec.
Answer = 1.0 m/sec to 1.2 m/sec
71. The design discharge for the separate sewer system shall be taken as_____________?.
A. equal to dry weather flow (DWF)
B. 2xDWF
C. 3 x DWF
D. 6xDWF.
Answer = 6xDWF
72. The minimum and maximum diameters of sewers shall preferably be_________________?.
A. 15 cm and 100 cm
B. 15 cm and 300 cm
C. 30 cm and 450 cm
D. 60 cm and 300cm.
Answer = 15 cm and 300 cm
73. Most suitable section of sewer in separate sewage system is________________?.
A. rectangular section
B. circular section
C. standard form of egg shaped sewer
D. modified egg shaped section.
Answer = circular section
74. The velocity of flow does not depend on_______________?.
A. grade of sewer
B. length of sewer
C. hydraulic mean depth of sewer
D. roughness of sewer.
Answer = length of sewer
75. The effect of increasing diameter of sewer on the self cleansing velocity is_____________?.
A. to decrease it
B. to increase it
C. fluctuating
D. nil.
Answer = to increase it
76. The type of sewer which is suitable for both combined and separate system is_____________?.
A. circular sewer
B. egg shaped sewer
C. horse-shoe type sewer
D. semi-elliptical sewer.
Answer = egg shaped sewer
77. The pathogens can be killed by_______________?.
A. nitrification
B. chlorination
C. oxidation
D. none of the above.
Answer = chlorination
78. Sewage treatment units are normally designed for______________?.
A. 5-10 years
B. 15-20 years
C. 30-40 years
D. 40-50 years.
Answer = 15-20 years
79. Standard BOD is measured at________________?.
A. 20°C – 1day
B. 25°C- 3day
C. 20°C – 5day
D. 30°C- 5day.
Answer = 20°C – 5day
80. The rate of BOD exerted at any time is_____________?.
A. directly proportional to BOD satisfied
B. directly proportional to BOD remain-ing
C. inversely proportional to BOD satisfied
D. inversely proportional to BOD re-maining.
Answer = directly proportional to BOD remain-ing
81. The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is______________?.
A. 1
B. 100
C. infinite
D. zero.
Answer = 100
82. Facultative bacteria are able to work in________________?.
A. presence of oxygen only
B. absence of oxygen only
C. presence as well as in absence of oxygen
D. presence of water.
Answer = presence as well as in absence of oxygen
83. Sewerage system is designed for_______________?.
A. maximum flow only
B. minimum flow only
C. average flow only
D. maximum and minimum flow.
Answer = maximum and minimum flow
84. Laying of sewers is usually done with the help of________________?.
A. a theodolite
B. a compass
C. sight rails and boning rods
D. a plane table.
Answer = sight rails and boning rods
85. If the sewage contains grease and fatty oils, these are removed in_________________?.
A. grit chambers
B. detritus tanks
C. skimming tanks
D. sedimentation tanks.
Answer = skimming tanks
86. Which of the following unit works in anaerobic conditions ?.
A. sludge digestion tank
B. sedimentation tank
C. activated sludge treatment
D. trickling filters.
Answer = sludge digestion tank
87. The maximum efficiency of BOD removal is achieved in______________?.
A. oxidation pond
B. oxidation ditch
C. aerated lagoons
D. trickling filters.
Answer = oxidation ditch
88. In facultative stabilization pond, the sewage is treated by________________?.
A. aerobic bacteria only
B. algae only
C. dual action of aerobic bacteria and anaerobic bacteria
D. sedimentation.
Answer = dual action of aerobic bacteria and anaerobic bacteria
89. Composting and lagooning are the methods of_______________?.
A. sludge digestion
B. sludge disposal
C. sedimentation
D. filtration.
Answer = sludge disposal
90. For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as___________________?.
A. 4.5 to 6.0
B. 6.5 to 8.0
C. 8.5 to 10.0
D. 10.5 to 12.0.
Answer = 6.5 to 8.0
91. For normal sludge, the value of sludge index for Indian conditions is________________?.
A. 0 to 50
B. 50 to 150
C. 150 to 350
D. 350 to 500.
Answer = 150 to 350
92. For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be__________________?.
A. X/4
B. X/2
C. X
D. 2X.
Answer = X/2
93. The gas from sludge digestion tank is mainly composed of __________________?.
A. nitrogen
B. carbon dioxide
C. hydrogen sulphide
D. methane.
Answer = methane
94. The process of lagooning is primarily a means of________________?.
A. reducing the excessive flow in sewers
B. disposing of sludge
C. increasing the capacity of storage re-servoirs
D. increasing flow of sewage through imhoff tanks.
Answer = disposing of sludge
95. A pipe which is installed in the house drainage to preserve the water seal of traps is called______________?.
A. vent pipe
B. antisiphonage pipe
C. waste pipe
D. soil pipe.
Answer = antisiphonage pipe
96. Most of the bacteria in sewage are______________?.
A. parasitic
B. saprophytic
C. pathogenic
D. anaerobic.
Answer = saprophytic
97. The pipe which is used to carry the discharge from sanitary fittings like bath rooms, kitchens etc. is called_______________?.
A. waste pipe
B. soil pipe
C. vent pipe
D. antisiphonage pipe.
Answer = waste pipe
98. When there is no recirculation of sewage, then recirculation factor is_______________?.
A. 0
B. 1
C. infinity
D. none of the above.
Answer = 1
99. Sludge volume index is defined as the ratio of_______________?.
A. percentage of sludge by volume to percentage of suspended solids by weight
B. percentage of sludge by volume to percentage of total solids by weight
C. percentage of suspended solids by weight to percentage of sludge by volume
D. percentage of total solids by weight to percentage of sludge by volume.
Answer = percentage of sludge by volume to percentage of suspended solids by weight
100. The main disadvantage of oxidation pond is that________________?.
A. large area is required for construction
B. maintenance and operation cost are high
C. BOD removal is very low
D. none of the above.
Answer = large area is required for construction
101. The detention period for oxidation ponds is usually kept as______________?.
A. 4-8 hours
B. 24 hours
C. 10 to 15 days
D. 3 months.
Answer = 10 to 15 days
102. The working conditions in imhoff tanks are_______________?.
A. aerobic only
B. anaerobic only
C. aerobic in lower compartment and anaerobic in upper compartment
D. anaerobic in lower compartment and aerobic in upper compartment.
Answer = anaerobic in lower compartment and aerobic in upper compartment
103. Generally the detention period for grit chambers is kept as_______________?.
A. 1 minute
B. 5 minutes
C. 2-4 hours
D. 12 hours.
Answer = 1 minute
104. Corrosion in concrete sewers is caused by______________?.
A. septic conditions
B. dissolved oxygen
C. chlorine
D. nitrogen.
Answer = septic conditions
105. Sewage treatment units are designed for_______________?.
A. maximum flow only
B. minimum flow only
C. average flow only
D. maximum and minimum flow.
Answer = average flow only
106. The means of access for inspection and cleaning of sewer line is known as_______________?.
A. inlet
B. manhole
C. drop manhole
D. catch basin.
Answer = manhole
107. Dissolved oxygen in streams is______________?.
A. maximum at noon
B. minimum at noon
C. maximum at midnight
D. same throughout the day.
Answer = maximum at noon
108. The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is______________?.
A. 1 ppm
B. 4 ppm
C. 10 ppm
D. 40 ppm.
Answer = 4 ppm
109. The ratio of 5 day BOD to ultimate BOD is about_______________?.
A. 1/3
B. 2/3
C. 3/4
D. 1.0.
Answer = 2/3
110. The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by_______________?.
A. TOD>BOD>COD
B. TOD>COD>BOD
C. BOD>COD>TOD
D. COD>BOD>TOD.
Answer = TOD>COD>BOD
111. Settling velocity increases with_______________?.
A. specific gravity of solid particles
B. size of particles
C. depth of tank
D. temperature of liquid.
Answer = depth of tank
112. Which of the following retards the self purification of stream ?.
A. higher temperature
B. sunlight
C. satisfying oxygen demand
D. none of the above.
Answer = none of the above
113. The characteristics of fresh and septic sewage respectively are____________________?.
A. acidic and alkaline
B. alkaline and acidic
C. both acidic
D. both alkaline.
Answer = alkaline and acidic
114. The most commonly used sewer under culverts is_______________?.
A. circular brick sewer
B. circular cast iron sewer
C. semi-elliptical sewer
D. horse-shoe type sewer.
Answer = circular brick sewer
115. An egg shaped section of sewer________________?.
A. is economical than circular section
B. provides self cleansing velocity at low discharges
C. is more stable than circular section
D. is easy to construct.
Answer = provides self cleansing velocity at low discharges
116. The main disadvantage of cement concrete sewers is________________?.
A. less strength
B. difficulty in construction
C. difficulty in transportation due to heavy weight
D. less life.
Answer = difficulty in transportation due to heavy weight
117. The design discharge for the combined sewer system shall be taken as________________?.
A. equal to rainfall
B. rainfall + DWF
C. rainfall + 2 DWF
D. rainfall + 6 DWF.
Answer = rainfall + 2 DWF
118. The slope of sewer shall be__________________?.
A. given in the direction of natural slope of ground
B. given in the direction opposite to natural slope of ground
C. zero
D. steeper than 1 in 20.
Answer = given in the direction of natural slope of ground
119. The specific gravity of sewage is_______________?.
A. much greater than 1
B. slightly less than 1
C. equal to 1
D. slightly greater than 1.
Answer = slightly greater than 1
120. If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be__________________?.
A. 4 mm/hr
B. lOmm/hr
C. 20 mm/hr
D. 40 mm/hr.
Answer = 40 mm/hr
121. The suitable system of sanitation for area of distributed rainfall throughout the year with less intensity is_________________?.
A. separate system
B. combined system
C. partially separate system
D. partially combined system.
Answer = combined system
122. Sewerage system is usually designed for_________________?.
A. 10 years
B. 25 years
C. 50 years
D. 75 years.
Answer = 25 years
123. For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be________________?.
A. separate system
B. combined system
C. partially combined system
D. partially separate system.
Answer = separate system
124. A sewer that receives the discharge of a number of house sewers is called________________?.
A. house sewer
B. lateral sewer
C. intercepting sewer
D. submain sewer.
Answer = lateral sewer
125. The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is____________________?.
A. reflux valve
B. sluice valve
C. air relief valve
D. pressure relief valve.
Answer = reflux valve
126. Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?.
A. circle method
B. equivalent pipe method
C. Hardy cross method
D. electrical analysis method.
Answer = equivalent pipe method
127. The layout of distribution system in which water flows towards the outer periphery is_________________?.
A. ring system
B. dead end system
C. radial system
D. grid iron system.
Answer = radial system
128. As compared to cast iron pipes, steel pipes are______________?.
A. heavier
B. stronger
C. costlier
D. less susceptible to corrosion.
Answer = stronger
129. Which of the following compounds is widely used for algae control ?.
A. sodium sulphate
B. copper sulphate
C. sodium chloride
D. calcium chloride.
Answer = copper sulphate
130. In lime-soda process________________?.
A. only carbonate hardness is removed
B. only non-carbonate hardness is re-moved
C. lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
D. lime reduces the non-carbonate hard-ness and soda-ash removes the carbo¬nate hardness.
Answer = lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
131. As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is___________________?.
A. smaller
B. larger
C. same
D. none of the above.
Answer = smaller
132. Which of the following chemical compounds can be used for dechlorination of water ?.
A. carbon dioxide
B. bleaching powder
C. sulphur dioxide
D. chloramines.
Answer = sulphur dioxide
133. The treatment of water with bleaching powder is known as________________?.
A. prechlorination
B. super chlorination
C. dechlorination
D. hypochlorination.
Answer = hypochlorination
134. The process in which the chlorination is done beyond the break point is known as_________________?.
A. prechlorination
B. post chlorination
C. super chlorination
D. break point chlorination.
Answer = super chlorination
135. Double filtration is used_______________?.
A. to increase the filtration slow sand filters capacity of
B. to increase the filtration rapid sand filters capacity of
C. for isolated buildings like pools, hotels etc swimming
D. all of the above.
Answer = to increase the filtration slow sand filters capacity of