Civil Engineering : Water Supply Engineering MCQs with Answers

1 .
The most commonly used chemical for dechlorination of water, is_____.
A)  sulphur-dioxide
B)  sodium sulphite
C)  sodium bisulphate
D)  sodium thiosulphate

Correct Answer :   sodium sulphite

2 .
The prescribed hardness limit of potable water ranges between_______.
A)  50 to 75 P.P.M.
B)  75 to 115 P.P.M.
C)  100 to 150 P.P.M.
D)  150 to 200 P.P.M.

Correct Answer :   75 to 115 P.P.M.

3 .
Capacity of soil to absorb moisture, is generally known as
A)  porosity
B)  permeability
C)  perviousness
D)  infiltration capacity

Correct Answer :   infiltration capacity

4 .
At break point of chlorination,
A)  residual chloride is zero
B)  chlorine is used to oxidise
C)  residual chlorine reappears
D)  residual chloride is maximum

Correct Answer :   residual chlorine reappears

5 .
Manholes are less common in______.
A)  cast iron pipes
B)  steel pipes
C)  R.C.C. pipes
D)  hume steel pipes

Correct Answer :   cast iron pipes

6 .
Pick up the correct statement from the following :
A)  If ports are closed, the dry intake towers will not have any water
B)  Even if ports are closed, the wet intake tower will have water filled up to reservoir level
C)  The dry intake towers are generally constructed with heavier construction to resist buoyant forces
D)  All of the above

Correct Answer :   All of the above

Explanation : * If ports are closed, the dry intake towers will not have any water
* Even if ports are closed, the wet intake tower will have water filled up to reservoir level
* The dry intake towers are generally constructed with heavier construction to resist buoyant forces
* No buoyant force acts on wet intake towers

7 .
The most ideal disinfectant used for drinking water throughout the world, is
A)  lime
B)  chlorine
C)  ammonia
D)  nitrogen

Correct Answer :   chlorine

8 .
A centrifugal pump is required to be primed before starting if it is located
A)  at higher level than water level of reservoir
B)  at lower level than water level of reservoir
C)  Both (A) and (B)
D)  Neither (A) nor (B)

Correct Answer :   at higher level than water level of reservoir

9 .
Raw water treated with only chlorine, is known as
A)  pre-chlorination
B)  de-chlorination
C)  plain chlorination
D)  first-chlorination

Correct Answer :   plain chlorination

10 .
Mathamoglobinemia or blue baby disease is caused due to
A)  Chlorides
B)  Sulphides
C)  Nitrates
D)  None of the above

Correct Answer :   Nitrates

11 .
Surge tanks are used________.
A)  for storage water
B)  to guard against water hammer
C)  as overflow valves
D)  to increase the velocity in a pipeline

Correct Answer :   to guard against water hammer

12 .
As per IS : 1172-1963, water required per head per day for average domestic purposes, is
A)  65 litres
B)  85 litres
C)  105 litres
D)  135 litres

Correct Answer :   135 litres

13 .
Before constructing a dam, the factor to be considered for controlling sedimentation, is
A)  selection of dam site
B)  construction of check dams
C)  providing vegetation screens
D)  All of the above

Correct Answer :   All of the above

Explanation : * selection of dam site
* construction of check dams
* providing vegetation screens
* providing under-sluices in the dam

14 .
The process of passing water through beds of granular materials, is called
A)  filtration
B)  screening
C)  sedimentation
D)  None of the above

Correct Answer :   filtration

15 .
If Q is discharge is cubicmetres per sec and D is the economical diameter of the pipe. According to Lea____.
A)  D = 0.67 to 0.87 √Q
B)  D = 0.77 to 0.97 √Q
C)  D = 0.97 to 1.22 √Q
D)  D = 1.22 to 1.33 √Q

Correct Answer :   D = 0.97 to 1.22 √Q

16 .
Water to the consumers may be supplied from________.
A)  ranney wells sunk to the water level
B)  infiltration galleries connected to sump well
C)  infiltration well dug out on the banks of rivers
D)  All of the above

Correct Answer :   All of the above

17 .
While determining the yield of open wells by the pumping test_____.
A)  velocity of recharging water, increases with depression head
B)  maximum safe yield of an open well, is expected at critical depression head
C)  depression head resulting at critical velocity, is called critical depression head
D)  All of the above

Correct Answer :   maximum safe yield of an open well, is expected at critical depression head

18 .
Increase in population of a rapidly growing city, may be estimated by_____.
A)  geometrical method
B)  arithmetical mean method
C)  incremental increase method
D)  graphical comparison method

Correct Answer :   geometrical method

19 .
The standard B.O.D. at 20&Deg;C, is taken for the consumption in____.
A)  2 days
B)  3 days
C)  4 days
D)  5 days

Correct Answer :   5 days

20 .
The superimposed load transmitted to the pipe, is generally evaluated by Bousiness formula_______.
A)  Pt = 3H³P / 2πZ
B)  Pt = 3H³P / 2πZ²
C)  Pt = 3H³P / 2πZ⁵
D)  Pt = 3H³P² / 2πZ³

Correct Answer :   Pt = 3H³P / 2πZ⁵

21 .
In slow sland filters, the turbidity of raw water can be removed only up to
A)  60 mg/litre
B)  75 mg/litre
C)  100 gm/litre
D)  150 mg/litre

Correct Answer :   60 mg/litre

22 .
If the average daily demand of a city of 50, 000 population, is 20 m.l.d., the maximum daily demand is_____.
A)  52 mld
B)  36 mld
C)  29 mld
D)  21 mld

Correct Answer :   36 mld

23 .
Recuperation test is carried out to determine_____.
A)  yield of well
B)  pH value of water
C)  turbidity of water
D)  discharge from a well

Correct Answer :   yield of well

24 .
Turbidity of water is expressed______.
A)  in ppm
B)  by pH value
C)  by colour code
D)  in numbers in an arbitrary scale

Correct Answer :   in ppm

25 .
Percussion drilling is unsuitable in_________.
A)  quick sand
B)  unconsolidated sand
C)  consolidated rocks
D)  unconsolidated gravel

Correct Answer :   consolidated rocks

26 .
Disinfection of water with ozone is not good because_______.
A)  it adds taste to the water
B)  it is more efficient than chlorine in killing bacterias
C)  it vanishes before water reaches the consumers
D)  it removes the colour, taste and odour from water as bacterias

Correct Answer :   it is more efficient than chlorine in killing bacterias

27 .
For centrifugal pumps______.
A)  initial cost is low
B)  limited space is required
C)  the discharge obtained is steady and non-pulsating
D)  All of the above

Correct Answer :   All of the above

28 .
The difference in the reservoir level and the lowest point of the water mains is 180 m. The expected pressure due to water hammer is 7.5 kg/cm² in a pressure conduit of diameter 1 m. Assuming the efficiency of the riveted joints of the pipe as 0.6 and minimum cover 3 mm for corrosion, the thickness of the pipe materials, is
A)  20 mm
A)  
B)  25 mm
B)  
C)  30 mm
C)  
D)  35 mm
D)  

Correct Answer :   20 mm

29 .
Low turbidity of water is detected by_______.
A)  Turbidity tube
B)  Baylis turbidimeter
C)  Hellipe turbidimeter
D)  Jackson turbidity meter

Correct Answer :   Baylis turbidimeter

30 .
While designing a water supply of an industrial township, industrial and commercial water demand of total supply, is assumed_______.
A)  10 to 15%
B)  15 to 20%
C)  20 to 25%
D)  None of the above

Correct Answer :   20 to 25%

31 .
The storage capacity of a reservoir may be divided into three zones. The lowest zone is____.
A)  Dead storage
B)  Useful storage
C)  Surcharge storage
D)  None of the above

Correct Answer :   Dead storage

32 .
The maximum pressure which the pipe can withstand without any leakage during hydrostatic pressure test, is called______.
A)  Test pressure
B)  Design pressure
C)  Working pressure
D)  Hydrostatic pressure

Correct Answer :   Test pressure

33 .
The level of underground water is called______.
A)  water level
B)  invert level
C)  water table
D)  negative level

Correct Answer :   water table

34 .
Per capita demand of water is calculated in litres______.
A)  per person per month
B)  per person per day
C)  per person per year
D)  None of the above

Correct Answer :   per person per day

35 .
Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be____.
A)  5
B)  10
C)  15
D)  nil

Correct Answer :   nil

36 .
Acidity in water is caused due to____.
A)  Free CO₂
B)  Mineral acids
C)  Iron sulphate
D)  All of the above

Correct Answer :   All of the above

37 .
The transitional middle portion of a logistic curve follows______.
A)  a constant rate
B)  a geometric growth
C)  a first over curve
D)  a logarithmic growth

Correct Answer :   a constant rate

38 .
The specific retention is least in case of_______.
A)  Clay
B)  Sand
C)  Coarse gravel
D)  Silt

Correct Answer :   Coarse gravel

39 .
Most commonly used pump for lifting water in water supply mains, is_____.
A)  rotary type pump
B)  axialflow pump
C)  centrifugal pumps
D)  reciprocating pump

Correct Answer :   axialflow pump

40 .
The ratio of the maximum daily consumption to the average daily demand, is____.
A)  1.2
B)  1.4
C)  1.6
D)  1.8

Correct Answer :   1.8

41 .
An earth formation which, although porous and capable of absoring water does not provide an appreciable supply to wells, is known as_____.
A)  acquifer
B)  aquifuge
C)  aquiclude
D)  None of the above

Correct Answer :   aquiclude

42 .
The cast iron pipes for water supply system are used for_______.
A)  strength
B)  durability
C)  easy connection
D)  All of the above

Correct Answer :   All of the above

Explanation : * strength
* durability
* easy connection
* low maintenance cost

43 .
For plain chlorination of water, the quantity of chlorine used, is_______.
A)  0.5 mg/litre
B)  0.4 mg/litre
C)  0.3 mg/litre
D)  0.2 mg/litre

Correct Answer :   0.5 mg/litre

44 .
For estimating the run off of catchments, the mean value of the constant 'K' in the Khosla's formula Qy = Py - K (1.8 Ty + 32) is
A)  1.31
A)  
B)  1.27
B)  
C)  1.25
C)  
D)  1.23
D)  

Correct Answer :   1.27

45 .
Pick up the correct statement from the following :
A)  The sum of specific yield and specific retention, is equal to porosity
B)  The ratio of volume drained to the total volume of material drained, is known as specific yield
C)  The volume of underground water extracted by gravity drainage from a saturated soil, is known as yield
D)  All of the above

Correct Answer :   All of the above

Explanation : * The sum of specific yield and specific retention, is equal to porosity
* The volume of underground water extracted by gravity drainage from a saturated soil, is known as yield
* The ratio of volume drained to the total volume of material drained, is known as specific yield
* The volume of water retained by the soil against the pull of gravity, is called specific retention or field capacity

46 .
In a rapid gravity filter_______.
A)  disinfected raw water is supplied
B)  raw water from the source is supplied
C)  raw water passed through coagulation tank is supplied
D)  None of the above

Correct Answer :   raw water passed through coagulation tank is supplied

47 .
In distribution pipes, air valves are provided at_______.
A)  lower points
B)  higher points
C)  junction points
D)  any where

Correct Answer :   higher points

48 .
Surcharge storage zone of a reservoir, is_______.
A)  below dead storage
B)  between dead storage and useful storage
C)  above useful storage
D)  also known as valley storage

Correct Answer :   above useful storage

49 .
Filtration of water is done to remove______.
A)  turbidity
B)  odour
C)  colour
D)  pathogenic bacteria

Correct Answer :   turbidity

50 .
Generally, first portion of a logistic curve for the population growth of a developing city, represents the growth of_________.
A)  increasing
B)  constant
C)  decreasing
D)  All of the above

Correct Answer :   increasing

51 .
Property of earth to allow water to pass through it, is known as______.
A)  permeability
B)  transmissibility
C)  porosity
D)  perviousness

Correct Answer :   perviousness

52 .
Water is supplied from the source to the treatment plant under gravity in
A)  Delhi
B)  Bombay
C)  Madras
D)  Calcutta

Correct Answer :   Bombay

53 .
P.V.C. pipes can withstand pressure bead of water upto______.
A)  50 m
B)  75 m
C)  100 m
D)  125 m

Correct Answer :   100 m

54 .
The population of a city in 2000 is 50,000. The average increase in population over last 8 decades is 7500 and average incremental increase during 8 decades is 750. The population of the city based on incremental method, in the year 2020 will be_______.
A)  60,500
B)  66,500
C)  72,500
D)  76,500

Correct Answer :   66,500

55 .
Air inlet valve in water mains, is generally provided at________.
A)  summit of the pipe
B)  upstream of sluice valve
C)  down stream of sluice valve
D)  Both (A) and (C)

Correct Answer :   Both (A) and (C)

56 .
The duration of contact of chlorine with water before it is served to the first consumer, should be at least________.
A)  20 to 30 minutes
B)  15 to 20 minutes
C)  10 to 15 minutes
D)  30 to 40 minutes

Correct Answer :   20 to 30 minutes

57 .
The diameter of pipes in bath rooms and lavatories in domestic water supply, is_______.
A)  24 mm
B)  18 mm
C)  12 mm
D)  6 mm

Correct Answer :   12 mm

58 .
m and n are monsoon duration factor and catchment factor respectively. If P is yearly rainfall in cm, runoff can be calculated by_______.
A)  velocity area method
B)  use of venturi-meter
C)  weir or spillway method
D)  using power plant consumption

Correct Answer :   velocity area method

59 .
Economic height of a dam is the height corresponding to which________.
A)  amount of silting is less
B)  cost of the dam per unit of storage is minimum
C)  free board provided is least
D)  cost of dam per unit storage is maximum

Correct Answer :   cost of the dam per unit of storage is minimum

60 .
Distribution mains of any water supply, is normally designed for its average daily requirement______.
A)  100%
B)  150%
C)  200%
D)  225%

Correct Answer :   225%

61 .
Pick up the correct statement from the following :
A)  At a particular speed of operation, the head produced decreases with the increase of discharge
A)  
B)  At a particular speed the discharge at which efficiency of a pump is maximum, is known as normal discharge
B)  
C)  The brake horse power required from the primemover to drive the pump, increases with the increase of discharge
C)  
D)  All of the above
D)  

Correct Answer :   Al of the above

Explaination : * At a particular speed of operation, the head produced decreases with the increase of discharge
* At a particular speed the discharge at which efficiency of a pump is maximum, is known as normal discharge
* The brake horse power required from the primemover to drive the pump, increases with the increase of discharge
* At zero discharge, discharge valve remaining closed, the head developed is maximum which is known as shut-off head

62 .
The maximum pressure to which a pipe is subjected to during its operation, is known
A)  test pressure
B)  pipe pressure
C)  working pressure
D)  design pressure

Correct Answer :   working pressure

63 .
If pH value of water is_____.
A)  7 water it is said to be neutral
B)  less than 7 it is said to be acidic
C)  more than 7 it is said to be alkaline
D)  All of the above

Correct Answer :   All of the above

64 .
In pressure supply mains, water hammer pressure is reduced by providing_______.
A)  pressure relief valves
B)  air valves
C)  sluice valves
D)  None of the above

Correct Answer :   pressure relief valves

65 .
Water supply system includes______.
A)  construction of dams
B)  construction of canals
C)  digging a well for water
D)  entire arrangement from source to distribution

Correct Answer :   entire arrangement from source to distribution

66 .
A high velocity of wash water is required for
A)  rapid gravity filter with strainers
B)  rapid gravity filter without strainers
C)  slow sand filter with strainers
D)  slow sand filter without strainers

Correct Answer :   rapid gravity filter without strainers

67 .
In distribution pipes, drain valves are provided at_________.
A)  higher point
B)  junction points
C)  lower point
D)  Any Where

Correct Answer :   lower point

68 .
To control the growth of algae in reservoirs, the compound which is used, is________.
A)  lime solution
B)  alum solution
C)  copper sulphate
D)  bleaching powder

Correct Answer :   copper sulphate

69 .
Pick up the wrong nominal internal diameter of cast iron (spun) pipes in mm from the following :
A)  550
B)  500
C)  400
D)  300

Correct Answer :   550

70 .
Hardness of water can be removed by boiling if it is due to
A)  calcium chloride
B)  calcium nitrates
C)  calcium sulphates
D)  calcium bicarbonates

Correct Answer :   calcium bicarbonates

71 .
A well is considered to be good if it is sunk into
A)  Clay
B)  Silt
C)  Sand
D)  Coarse gravel

Correct Answer :   Coarse gravel

72 .
The nitrate concentration in domestic water supplies, is generally limited to____.
A)  30 ppm
B)  45 ppm
C)  15 ppm
D)  25 ppm

Correct Answer :   45 ppm

73 .
Mathamoglobinemia, or blue baby disease is caused due to
A)  nitrates
B)  nitrites
C)  chlorides
D)  sulphides

Correct Answer :   nitrates

74 .
The main process to purify water by filtration, is_______.
A)  electronic change
B)  mechanical straining
C)  flocculation and sedimentation
D)  All of the above

Correct Answer :   All of the above

Explanation : * electronic change
* mechanical straining
* flocculation and sedimentation
* biological metabolism

75 .
Surface water is obtained from
A)  rain
B)  well
C)  springs
D)  artesian well

Correct Answer :   rain

76 .
Sluice valves in main water supplies______.
A)  are spaced about 5 km apart
B)  are usually placed at the summits
C)  are used to regulate the flow of water in pipes
D)  All of the above

Correct Answer :   All of the above

77 .
Dead storage of a reservoir of Q capacity generally provided for silt deposition during its life time, is generally kept___.
A)  1/3rd Q
B)  1/4th Q
C)  1/5th Q
D)  1/6th Q

Correct Answer :   1/4th Q

78 .
If the specific capacity of a well is 0.3183 x 10⁻³ per sec, the discharge from a well of 4 m diameter under a depression head of 4 m, is
A)  12 litres/sec
A)  
B)  14 litres/sec
B)  
C)  16 litres/sec
C)  
D)  None of the above
D)  

Correct Answer :   16 litres/sec

79 .
The factor to be considered for the source of city water supply, is
A)  elevation of the source of water
B)  general terrain intervening the area
C)  quantity and quality of the available water
D)  All of the above

Correct Answer :   All of the above

80 .
Yield of a drainage basin is :
A)  average run off over a short period
B)  run off of the area expressed as instantaneous rate
C)  total volume of water flowing annually
D)  All of the above

Correct Answer :   total volume of water flowing annually

81 .
Yield of a drainage basin is :
A)  average run off over a short period
B)  run off of the area expressed as instantaneous rate
C)  total volume of water flowing annually
D)  All of the above

Correct Answer :   total volume of water flowing annually

82 .
Flow through period, in sedimentation tanks, is
A)  less than detention period
B)  more than detention period
C)  equal to detention period
D)  detention period divided by displacement efficiency

Correct Answer :   less than detention period

83 .
Normal values of overflow rate for plain sedimentation tank, is_____.
A)  250 to 500 litres/hr/m²
B)  500 to 750 litres/hr/m²
C)  750 to 1000 litres/hr/m²
D)  1000 to 1250 litres/hr/m²

Correct Answer :   500 to 750 litres/hr/m²

84 .
The force which develops in a pressure conduit supported on trestles, is______.
A)  tension
B)  compression
C)  temperature stress
D)  flexural stress

Correct Answer :   flexural stress

85 .
After cleaning a slow sand filter, the filtered water is not used for
A)  24 hours to 36 hours
B)  18 hours to 24 hours
C)  12 hours to 18 hours
D)  6 hours to 12 hours

Correct Answer :   24 hours to 36 hours

86 .
A pressure conduit laid under ground, may not be subjected to_____.
A)  internal pressure of water
B)  pressure due to external load
C)  longitudinal temperature stress
D)  longitudinal stresses due to unbalanced pressure to bends

Correct Answer :   longitudinal temperature stress

87 .
Service connections to consumers houses, are generally provided with
A)  hume pipes
B)  copper pipes
C)  P.V.C. pipes
D)  galvanised iron pipes

Correct Answer :   galvanised iron pipes

88 .
The maximum permitted loss of head in a rapid sand filter, is_____.
A)  4 m
B)  3 m
C)  2 m
D)  1 m

Correct Answer :   3 m

89 .
For maximum alkalinity of water, pH value should be_____.
A)  21
B)  14
C)  less than 7
D)  zero

Correct Answer :   14

90 .
The fire demand for a city of 50, 000 population, according to Godrich formula, is______.
A)  44 mld
B)  42 mld
C)  40 mld
D)  34 mld

Correct Answer :   44 mld

91 .
Perched acquifers generally occur
A)  in acquicludes
B)  in artesian acquifers
C)  above water table
D)  below water table

Correct Answer :   above water table

92 .
Silt storage is the same as________.
A)  live storage
B)  effective storage
C)  Both (A) and (B)
D)  dead storage

Correct Answer :   dead storage

93 .
For complete stabilisation of organic matter in polluted water, it takes
A)  40 days
B)  30 days
C)  20 days
D)  10 days

Correct Answer :   30 days

94 .
A pressure conduit carrying water beneath a stream or a canal, is known as______.
A)  sag
B)  depressed pipe
C)  inverted syphon
D)  All of the above

Correct Answer :   All of the above

95 .
For 3.25 x 10⁻² cumecs discharging from a well, a pump is installed to lift water against a total head of 30 m. The minimum required horse power, is
A)  20 H.P
A)  
B)  18 H.P
B)  
C)  15 H.P
C)  
D)  10 H.P
D)  

Correct Answer :   20 H.P

96 .
Surface water may___.
A)  be contaminated by impurities
B)  contain large amount of impurities
C)  contain disease producing bacterias
D)  All of the above

Correct Answer :   All of the above

97 .
For a city developed haphazardly, the layout of distribution pipes preferred to, is
A)  dead end system
B)  ring system
C)  radial system
D)  grid iron system

Correct Answer :   dead end system

98 .
Asbestos pipes are joined by means of
A)  flanged joint
B)  flexible joint
C)  simplex joint
D)  dresser coupling joint

Correct Answer :   simplex joint

99 .
Abyssinian tube well is a special type of_______.
A)  cavity type wells
B)  strainer type well
C)  slotted type wells
D)  None of the above

Correct Answer :   strainer type well

100 .
Corrosion of well pipes may not be reduced by_______.
A)  using thicker pipes
B)  reducing the flow velocity
C)  using screens having larger area of openings
D)  reducing the draw down and the pumping rate

Correct Answer :   using screens having larger area of openings

101 .
Manholes along the mains from the source to a city are provided at 500 m intervals in______.
A)  R.C.C. pipes
B)  steel pipes
C)  hume steel pipes
D)  All of the above

Correct Answer :   All of the above

102 .
The population growth curve is_________.
A)  S-shaped curve
B)  straight line
C)  circular curve
D)  parabolic curve

Correct Answer :   S-shaped curve

103 .
Turbidity of raw water is a measure of
A)  B.O.D.
B)  acidity of water
C)  suspended solids
D)  None of the above

Correct Answer :   suspended solids

104 .
Normal values of overflow rate for plain sedimentation tank using coagulants, is__________.
A)  750 to 1000 litres/hr/m²
B)  1000 to 1250 litres/hr/m²
C)  1250 to 1500 litres/hr/m²
D)  1500 litres/hr/m²

Correct Answer :   1000 to 1250 litres/hr/m²

105 .
The formula Q = P - K[1.8T + 32] in which Q is runoff, P is annual rain fall in cm, T is mean annual temperature in centigrades and K is a constant, is known
A)  English formula
A)  
B)  Khosla's formula
B)  
C)  Justin's formula
C)  
D)  Vermule's formula
D)  

Correct Answer :   Khosla's formula

106 .
Aqueducts are generally designed
A)  circular
B)  rectangular
C)  horse shoe section
D)  All of the above

Correct Answer :   All of the above

107 .
Carbonates in water produce________.
A)  temporary hardness
B)  acidity
C)  alkanity
D)  permanent hardness

Correct Answer :   temporary hardness

108 .
The period of cleaning of a slow sand filter, is usually
A)  5 to 10 days
B)  two weeks to three weeks
C)  one month to three months
D)  three months to six months

Correct Answer :   one month to three months

109 .
At the socket and spigot joint,________.
A)  spigot is fitted into the socket
B)  enlarged end of the pipe is called socket
C)  normal end of the pipe is called spigot
D)  All of the above

Correct Answer :   All of the above

Explanation : * spigot is fitted into the socket
* enlarged end of the pipe is called socket
* normal end of the pipe is called spigot
* molten lead is used for water proofing

110 .
Continuous flow of water can be expected from_______.
A)  surface springs
B)  artesian springs
C)  gravity springs
D)  None of the above

Correct Answer :   artesian springs

111 .
The maximum hourly consumption, is generally taken as_______.
A)  120%
B)  130%
C)  140%
D)  150%

Correct Answer :   150%

112 .
During treatment of water, sedimentation is done
A)  before filtration
B)  after filtration
C)  along with chlorination
D)  simultaneously with filtration

Correct Answer :   before filtration

113 .
When the reduced level of the water source is higher than the reduced level of the consumer's place, water is generally supplied________.
A)  by pumping system
B)  by gravitational system
C)  Both (A) and (B)
D)  None of the above

Correct Answer :   by gravitational system

114 .
Most commonly used section in grade aqueducts, is_____.
A)  circular
B)  parabolic
C)  rectangular
D)  horse shoe section

Correct Answer :   rectangular

115 .
The lowest outlet sluice in a dam is provided
A)  below the dead storage
B)  at the centre of the dam
C)  on the top level of dead storage
D)  on the top level of useful storage

Correct Answer :   on the top level of dead storage

116 .
The four major water supply distribution systems, are_______.
A)  tree, grid iron, ring and radial
B)  dead end, tree, grid iron and circular
C)  tree, reticulation, circular and ring
D)  dead end, tree, grid iron and reticulation

Correct Answer :   tree, grid iron, ring and radial

117 .
Most important source of water for public water supply, is from_____.
A)  ponds
B)  lakes
C)  rivers
D)  sea

Correct Answer :   sea

118 .
Chlorination of water does not remove
A)  B.O.D
B)  dissolved oxygen
C)  ammonia content
D)  organic matter content

Correct Answer :   dissolved oxygen

119 .
The efficiency of a pumping set, is generally assumed_______.
A)  70%
B)  65%
C)  60%
D)  55%

Correct Answer :   65%

120 .
To remove very fine suspended particles from water, the method adopted is_____.
A)  boiling
B)  screening
C)  filtration
D)  sedimentation

Correct Answer :   filtration

121 .
Velocity of flow of water in plain sedimentation water tank, is normally kept______.
A)  30 cm/minute
B)  20 cm/minute
C)  10 cm/minute
D)  5 cm/minute

Correct Answer :   30 cm/minute

122 .
Normal values of overflow rate for sedimentation tanks using coagulants in litres/hr/m2 , generally range between_______.
A)  250 to 500
B)  500 to 750
C)  750 to 1000
D)  1000 to 1250

Correct Answer :   1000 to 1250

123 .
In a rapid sand filter, air binding is caused due to excessive________.
A)  pressure
B)  negative pressure
C)  turbidity
D)  water pressure

Correct Answer :   negative pressure

124 .
If average volume of sediment deposits is one-tenth million cubic metres per year in a reservoir of total capacity 10 million cubic metres, the dead storage will be filled up, in_______.
A)  10 years
B)  15 years
C)  20 years
D)  25 years

Correct Answer :   25 years

125 .
Most important method for calculating discharge for planning a water supply project, is
A)  use of venturi-meter
B)  weir or spillway method
C)  velocity area method
D)  using power plant consumption

Correct Answer :   velocity area method

126 .
Alkalinity in water may be caused due to__________.
A)  sodium carbonate
B)  calcium hydroxide
C)  calcium and magnesium bicarbonates
D)  All of the above

Correct Answer :   All of the above

127 .
The maximum depth of sedimentation tanks is limited to_____.
A)  6 m
B)  5 m
C)  4 m
D)  3 m

Correct Answer :   6 m

128 .
By boiling water, hardness can be removed if it is due to_____.
A)  calcium nitrate
B)  calcium bicarbonate
C)  calcium sulphate
D)  magnesium sulphate

Correct Answer :   calcium bicarbonate

129 .
For determining the velocity of flow of underground water, the most commonly used non-empirical formula is__________.
A)  Lacy's formula
B)  Darcy's formula
C)  Hazen's formula
D)  Slichter's formula

Correct Answer :   Darcy's formula

130 .
The least thickness of class B cast iron (spun) pipe, is_______.
A)  7.2 mm
B)  7.9 mm
C)  8.6 mm
D)  10 mm

Correct Answer :   8.6 mm

131 .
The R.L. of ground water table on the sides of a valley is 1505 m whereas R.L. of the stream water is 1475 m. If 60° slope consists of pervious soil between R.L. 1485 m to 1500 m, the gravity spring may be expected at the point of reduced level
A)  1485 m
A)  
B)  1475 m
B)  
C)  1500 m
C)  
D)  1505 m
D)  

Correct Answer :   1485 m

132 .
Hardness of water is caused by_____.
A)  turbidity
B)  presence of soap lather
C)  presence of chlorides and sulphates of sodium and potassium
D)  presence of bicarbonates, sulphates or chlorides of calcium and magnesium

Correct Answer :   presence of bicarbonates, sulphates or chlorides of calcium and magnesium

133 .
Coli bacterias die in water having pH greater than
A)  9.5
B)  8.5
C)  7.5
D)  6.5

Correct Answer :   9.5

134 .
Check valves are installed_________.
A)  on the delivery side of the pumping set
B)  at the interconnections between polluted water system and a potable water system
C)  Both (A) and (B)
D)  Neither (A) nor (B)

Correct Answer :   Both (A) and (B)

135 .
If intensity of rainfall in cm per hour is I, percentage coefficient of run-off is P, area of catchment in square kilometres is A, the total run-off Q, is given by
A)  Q = 1.758 x 10² x API
A)  
B)  Q = 2.758 x 10² x API
B)  
C)  Q = 2.758 x 10³ x API
C)  
D)  None of the above
D)  

Correct Answer :   Q = 2.758 x 10³ x API

136 .
In pumping stations, the type of joint generally used, is_________.
A)  flanged joint
B)  expansion joint
C)  dresser coupling joint
D)  socket and spigot joint

Correct Answer :   flanged joint

137 .
The permissible pH value for public water supplies may range between
A)  8.5 to 10.5
B)  6.5 to 8.5
C)  5.5 to 6.5
D)  4.5 to 5.5

Correct Answer :   6.5 to 8.5

138 .
The strainer type tube well, is unsuitable for________.
A)  fine sandy strata
B)  clean gravels
C)  coarse gravels
D)  None of the above

Correct Answer :   fine sandy strata

139 .
Specific capacity or yield of wells, is generally expressed, as
A)  m³/hour
B)  m³ per sec
C)  m³/hour/m²
D)  m³/hour/m²/m

Correct Answer :   m³/hour/m²/m

140 .
The most important and widely used tube well in India, is_______.
A)  cavity well
B)  slotted well
C)  strainer well
D)  perforated pipe well

Correct Answer :   strainer well

141 .
The maximum permissible chloride content in treated water of public water supplies should not exceed_______.
A)  250 P.P.M.
B)  200 P.P.M.
C)  150 P.P.M.
D)  100 P.P.M.

Correct Answer :   250 P.P.M

142 .
A circular gravity aqueduct is not generally preferred to because of_______.
A)  minimum cost of construction
B)  its proper support on the ground.
C)  its maximum hydraulic mean depth
D)  maximum area per unit of wetted perimeter

Correct Answer :   its proper support on the ground.

143 .
Standard unit of turbidity of water is in one litre of distilled water, one milligram of finely divided______.
A)  mud
B)  clay
C)  silica
D)  organic matter

Correct Answer :   silica

144 .
Water losses in water supply, is assumed as______.
A)  7.5%
B)  10%
C)  15%
D)  22.5%

Correct Answer :   15%

145 .
The pH value of water is kept slightly less than 7 so that hydrochloride ions may combine with ammonia ions to form_______.
A)  Di-chloramine (NH₂Cl)
B)  Mono-chloramine (NHCl)
C)  Nitrogen trichloramine (NCl₃)
D)  All of the above

Correct Answer :   All of the above

146 .
'Shrouding' is essentially provided in______.
A)  slotted type well
B)  cavity type wells
C)  strainer type wells
D)  All of the above

Correct Answer :   slotted type well

147 .
The ensure proper growth of children's teeth, the quantity of flouride used in water mains, is____.
A)  4 mg/litre
B)  3 mg/litre
C)  2 mg/litre
D)  1 mg/litre

Correct Answer :   1 mg/litre

148 .
Open channels supported over tres-les, are generally known as
A)  flumes
B)  syphons
C)  acqueducts
D)  raised canals

Correct Answer :   flumes

149 .
For least effect on the water table, the tube wells must be dug one in every
A)  1.0 sq km
B)  1.5 sq km
C)  1.25 sq km
D)  1.75 sq km

Correct Answer :   1.5 sq km

150 .
In plain sedimentation tanks under normal conditions, impurities are removed upto_____.
A)  90%
B)  80%
C)  70%
D)  60%

Correct Answer :   70%

151 .
The valve fitted closely in a recess against an opening in a pipe, is generally_____.
A)  spherical disc
B)  parallelopiped disc
C)  wedge shaped circular disc
D)  conical shaped circular disc

Correct Answer :   wedge shaped circular disc

152 .
For calculation of economical diameter D of a pipe in metres for a discharge Q to be pumped in cumecs, Lea suggested the empirical formula_____.
A)  D = 3.22 √Q
B)  D = 2.22 √Q
C)  D = 2.02 √Q
D)  D = 1.22 √Q

Correct Answer :   D = 1.22 √Q

153 .
The factor affecting per capita demand, is_____.
A)  cost of water
B)  size of the city
C)  climatic conditions
D)  All of the above

Correct Answer :   All of the above

Explanation : * cost of water
* size of the city
* climatic conditions
* pressure in water mains

154 .
Pick up the incorrect statement from the following. The underground sources of water, is from_____.
A)  infiltration wells
B)  wells
C)  springs
D)  storage reservoirs

Correct Answer :   infiltration wells

155 .
Disinfection of drinking water, is done to remove_______.
A)  odour
B)  bacterias
C)  colour
D)  turbidity

Correct Answer :   bacterias

156 .
The expected discharge to be obtained from an open well sunk in coarse sand is 0.0059 cumec. If the working depression head of the well is 3 m, the minimum diameter of the well, is____.
A)  2.25 m
B)  2.50 m
C)  3.00 m
D)  4.50 m

Correct Answer :   3.00 m

157 .
Average annual rainfall at any station is the average of annual rainfall over a period of
A)  35 years
B)  28 years
C)  21 years
D)  14 years

Correct Answer :   35 years

158 .
Time of concentration_____.
A)  duration of rainfall
B)  is the time taken, for precipitation
C)  time taken for all the ran off to reach the drain
D)  time taken for the storm water to travel from the most remote point to the drain.

Correct Answer :   time taken for the storm water to travel from the most remote point to the drain.

159 .
If four fires break out in a city of population 40 lakhs and if each hydrant has three streams and duration of each fire is four hours, the total quantity of water required, is______.
A)  1880 kilo litres
B)  2880 kilo litres
C)  3880 kilo litres
D)  4880 kilo litres

Correct Answer :   2880 kilo litres

160 .
A slow sand filter is cleaned if its filter head is higher than______.
A)  20 cm to 40 cm
B)  40 cm to 70 cm
C)  70 cm to 120 cm
D)  120 cm to 150 cm

Correct Answer :   70 cm to 120 cm

161 .
Water having pH value as 6, is_____.
A)  acidic
B)  neutral
C)  alkaline
D)  All of the above

Correct Answer :   acidic

162 .
Perched acquifers are generally found______.
A)  below the water table
B)  on the surface of the ground
C)  below the surface of the ground but above water table
D)  None of the above

Correct Answer :   below the surface of the ground but above water table

163 .
Detention period of a settling tank is________.
A)  average time for which water is retained in tank
B)  time required for flow of water to fill the tank fully
C)  average theoretical time required for water to flow through the tank
D)  All of the above

Correct Answer :   All of the above

164 .
The order of existence of three portions of water in a reservoir from the bottom to top is________.
A)  useful storage + dead storage + surcharge storage
B)  dead storage + useful storage + surcharge storage
C)  useful storage + surcharge storage + dead storage
D)  surcharge storage + useful storage + dead storage

Correct Answer :   dead storage + useful storage + surcharge storage

165 .
The approximate diameter of a water mains for supplying 7.2 mld with a velocity 1.2 m/sec, is______.
A)  30 cm
B)  28 cm
C)  26 cm
D)  24 cm

Correct Answer :   30 cm

166 .
Hard water contains_____.
A)  calcium
B)  magnesium sulphate
C)  magnesium bicarbonates
D)  All of the above

Correct Answer :   All of the above

167 .
An area is declared drought affected if its mean rainfall is less than______.
A)  75%
B)  80%
C)  85%
D)  100%

Correct Answer :   85%

168 .
The best quality of filter material is obtained from quartzite if it does not loose weight when placed in hydro-chloric acid for 24 hours, more than_____.
A)  5%
B)  10%
C)  12%
D)  15%

Correct Answer :   5%

169 .
Cast iron pipes are generally preferred to, because
A)  of durability
B)  of longer life
C)  of ease to join
D)  All of the above

Correct Answer :   All of the above

170 .
To detect the turbidity of the order of 0 to 1000 P.P.M. the instrument used is______.
A)  turbidimeter
B)  Baylis turbidimeter
C)  Jackson turbidimeter
D)  Hallige turbidimeter

Correct Answer :   Baylis turbidimeter

171 .
Standard process of chlorination of water, is done by_____.
A)  post-chlorination
B)  pre-chlorination
C)  plain chlorination
D)  double chlorination

Correct Answer :   pre-chlorination

172 .
Water gets evaporated from water surfaces and land surfaces, get converted into water drops at lower temperatures, flows over ground surface and finally meets its source, i.e. lake, sea, etc. This entire process is generally known as______.
A)  water cycle
B)  hydrological cycle
C)  evaporation and precipitation cycle
D)  All of the above

Correct Answer :   All of the above

173 .
Disappearance of pink colour of water of a well due of KMnO4 indicates that water contains____.
A)  turbidity
B)  acidity
C)  organic matter
D)  None of the above

Correct Answer :   organic matter

174 .
The type of joint generally used in cast iron pipes, is______.
A)  flexible joint
B)  flanged joint
C)  dresser coupling joint
D)  All of the above

Correct Answer :   All of the above

Explanation : * flexible joint
* flanged joint
* dresser coupling joint
* socket and spigot joint

175 .
Growth of population can be conveniently represented by_____.
A)  a logistic curve
B)  an arithmetical curve
C)  a straight line curve
D)  a semi-logarithmic curve

Correct Answer :   a logistic curve

176 .
Air valves are generally provided in pressure pipes of water supply_________.
A)  at low points
B)  at summits
C)  at pipe junctions
D)  near service pipes

Correct Answer :   at summits

177 .
Bacterias which can survive with or without free oxygen, are known_____.
A)  aerobic bacterias
B)  anerobic bacterias
C)  Both (A) and (B)
D)  facultative bacterias

Correct Answer :   facultative bacterias

178 .
The maximum permissible colour for domestic supplies based on cobalt scale, is_____.
A)  10 ppm
B)  15 ppm
C)  20 ppm
D)  25 ppm

Correct Answer :   20 ppm

179 .
The dilution ratio at which the odour is hardly detectable is generally called threshold odour number and for public supplies it should not exceed____.
A)  3
B)  5
C)  7
D)  9

Correct Answer :   3

180 .
Chemical coagulation of drinking water, is done_______.
A)  to remove the bacterias
B)  to settle suspended materials
C)  Both (A) and (B)
D)  to increase rate of settlement of suspended materials

Correct Answer :   to increase rate of settlement of suspended materials

181 .
Permanent hardness of water can be removed by____.
A)  adding lime
B)  zeolite process
C)  adding alum
D)  adding chlorine

Correct Answer :   zeolite process

182 .
Demand for public uses in a city, does not include water required for______.
A)  drinking purposes
B)  sprickling on roads
C)  watering of public parks
D)  watering of public gardens

Correct Answer :   drinking purposes

183 .
In an artesian acquifer, the draw downs in two observation wells at distances 100 m, and 200 m were found same after one hour and x hours respectively. The value of x, is____.
A)  16 hours
B)  9 hours
C)  4 hours
D)  2 hours

Correct Answer :   4 hours

184 .
The maximum non-verticality of the bore of a well 200 m deep, may be permitted up to____.
A)  50 cm
B)  75 cm
C)  100 cm
D)  150 cm

Correct Answer :   100 cm

185 .
By adding 1 ml of orthotolidine solution to 100 ml chlorinated water taken after contact period, the residual chlorine makes the colour of solution____.
A)  bluish
B)  reddish
C)  greenish
D)  yellowish

Correct Answer :   yellowish

186 .
The chlorine supply cylinders are generally kept at 38°C to 40°C to prevent_____.
A)  it from burning
B)  conversion into crystals
C)  it from explosion
D)  None of the above

Correct Answer :   conversion into crystals

187 .
The fire demand of a city may be worked out by________.
A)  Bustan's formula
B)  Freeman formula
C)  Kuichling's formula
D)  All of the above

Correct Answer :   All of the above

Explanation : * Bustan's formula
* Freeman formula
* Kuichling's formula
* Under Writers formula

188 .
Steel pipe are________.
A)  likely to last 100 years under ordinary conditions
B)  connected by riveted or welded joints
C)  suitable for withstanding high internal pressure
D)  generally laid under ground and no expansion joint is required

Correct Answer :   likely to last 100 years under ordinary conditions

189 .
If discharge of a pump is 0.16 cumecs, the economic diameter of pipe, is
A)  0.488 m
B)  0.488 cm
C)  4.88 m
D)  4.88 cm

Correct Answer :   0.488 m

190 .
Hard water for public water supply is discarded because
A)  it contains lot of turbidity
B)  it consumes more soap
C)  it possesses bad taste and odour
D)  it contains pathogenic bacterias

Correct Answer :   it consumes more soap

191 .
Quality of water is said to be good if it is________.
A)  colourless
B)  tasteless
C)  free from suspended matter
D)  All of the above

Correct Answer :   All of the above

Explanation : * colourless
* tasteless
* free from suspended matter
* free from pathogenic organism

192 .
The main draw-back of centrifugal pump, is
A)  necessity of priming
B)  the suction lift is limited to 6 m
C)  for high heads, efficiency is low up to 50%
D)  All of the above

Correct Answer :   All of the above

Explanation : * necessity of priming
* the suction lift is limited to 6 m
* for high heads, efficiency is low up to 50%
* discharge from pump varies with the load of water

193 .
Distribution of wash water is provided in
A)  slow sand filter
B)  sedimentation tank
C)  rapid gravity filter
D)  All of the above

Correct Answer :   rapid gravity filter

194 .
The valves provided at low points of pipes to drain off water quickly under gravity, are called_______.
A)  sewer valves
B)  drain valves
C)  blow off valves
D)  All of the above

Correct Answer :   All of the above

195 .
The bacterias which require free oxygen for their survival, are called________.
A)  Aerobic bacterias
B)  Anaerobic bacterias
C)  Faculative bacteria
D)  None of the above

Correct Answer :   Aerobic bacterias

196 .
The water level in an open well was depressed by pumping 2.5 m and recuperated 2.87 m in 3 hours and 50 minutes. The yield of the well per minute is____.
A)  0.0066
B)  0.0055
C)  0.0044
D)  0.0033

Correct Answer :   0.0055

197 .
Rapid gravity filter can only remove turbidity of water upto____.
A)  25 to 30 gm/litre
B)  30 to 35 cm/litre
C)  35 to 40 gm/litre
D)  50 gm/litre

Correct Answer :   35 to 40 gm/litre

198 .
The best process of disinfection of public water supply, is by______.
A)  boiling
B)  chlorination
C)  adding lime
D)  adding zone

Correct Answer :   chlorination

199 .
The type of pipe commonly used in water supply distribution schemes, is
A)  Hume pipes
B)  G.I. pipes
C)  R.C.C. pipes
D)  Cast iron pipes

Correct Answer :   Cast iron pipes

200 .
The population of a city in 2000 is 50, 000. The average per decade of the previous records of population is 5000 and average percentage per decade is 20%. The population of the city based on geometrical increase method, in the year 2020 will be_____.
A)  72, 000
A)  
B)  70, 000
B)  
C)  64, 000
C)  
D)  60, 000
D)  

Correct Answer :   72, 000

201 .
Detention time for plain sedimentation tank usually ranges from_______.
A)  4 to 8 hours
B)  6 to 10 hours
C)  8 to 12 hours
D)  12 to 16 hours

Correct Answer :   4 to 8 hours

202 .
For a network of distribution pipes of a proposed township shown in the below figure, the layout of distribution system, is
A)  ring system
A)  
B)  dead end system
B)  
C)  radial system
C)  
D)  grid-iron system
D)  

Correct Answer :   radial system

203 .
The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of_____.
A)  6 kg/cm²
B)  7 kg/cm²
C)  8 kg/cm²
D)  10 kg/cm²

Correct Answer :   7 kg/cm²

204 .
Slow sand filter is used if maximum turbidity of raw water is less than____.
A)  30 gm/litre
B)  40 gm/litre
C)  50 gm/litre
D)  None of the above

Correct Answer :   50 gm/litre

205 .
The total domestic consumption in a city water supply, is assumed
A)  60%
B)  40%
C)  30%
D)  20%

Correct Answer :   60%

206 .
Pressure relief valves are provided in water mains________.
A)  at low points
B)  upstream of sluice
C)  to reduce the pressure
D)  All of the above

Correct Answer :   All of the above

207 .
The percentage of chlorine in fresh bleaching powder is roughly______.
A)  20 to 25
B)  30 to 35
C)  40 to 50
D)  50 to 60

Correct Answer :   30 to 35

208 .
Higher yield may be expected from______.
A)  gravity springs
B)  artesian springs
C)  surface springs
D)  All of the above

Correct Answer :   artesian springs

209 .
In rapid sand filters the ratio of length and diameter of the lateral, should not be greater than
A)  10
B)  15
C)  20
D)  25

Correct Answer :   20

210 .
Underground water is obtained from____.
A)  springs
B)  lakes
C)  rivers
D)  reservoirs

Correct Answer :   springs

211 .
Run off is the quantity of water which flows
A)  in rivers
B)  in sewer pipes
C)  due to leakage in pipes
D)  All of the above

Correct Answer :   in rivers

212 .
Efficiency of removing bacterias from raw water by a slow sand filter, is____.
A)  80% to 81%
B)  85% to 86%
C)  90% to 97%
D)  98% to 99%

Correct Answer :   98% to 99%

213 .
A water channel supported above the ground over trestles, is generally called____.
A)  canal
B)  flume
C)  tunnel
D)  adueduct

Correct Answer :   flume

214 .
One degree of hardness of water means a content of salts of_____.
A)  10.25 mg/litre
B)  12.25 mg/litre
C)  14.25 mg/litre
D)  16.25 mg/litre

Correct Answer :   14.25 mg/litre

215 .
The pH value of water fit for drinking, is______.
A)  7
B)  9
C)  11
D)  15

Correct Answer :   7

216 .
Water may not contain much impurities if its source is____________.
A)  reservoirs
B)  lakes in lower regions
C)  spring along hill slopes
D)  stream flowing in plains

Correct Answer :   spring along hill slopes

217 .
The requirement of water per capita per day, is____.
A)  300 litres
B)  200 litres
C)  150 litres
D)  90 litres

Correct Answer :   90 litres

218 .
If n is porosity, y is specific yield and r is specific retention of any soil, the relationship which holds good, is_____.
A)  n + y = r
B)  y + r = n
C)  n + r + y = 0
D)  n + y + r = 1

Correct Answer :   y + r = n

219 .
When gravity and pumping systems of water distribution are adopted, the type of distribution reservoir, is____.
A)  intz tank
B)  elevated tank
C)  stand pipe
D)  ground source reservoir

Correct Answer :   elevated tank

220 .
Normal values of overflow rate for plain sedimentation tanks in litres/hr/m², generally range between
A)  100 to 250
A)  
B)  250 to 500
B)  
C)  500 to 750
C)  
D)  750 to 1000
D)  

Correct Answer :   500 to 750

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