Water Supply Engineering most important questions

Question No. 01
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) All the above
Answer: Option B

Question No. 02
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
Answer: Option C

Question No. 03
In pressure supply mains, water hammer pressure is reduced by providing
(A) Sluice valves
(B) Air valves
(C) Pressure relief valves
(D) None of these
Answer: Option C

Question No. 04
Specific capacity or yield of wells, is generally expressed, as
(A) m3 per sec
(B) m3/hour
(C) m3/hour/m2
(D) m3/hour/m2/m
Answer: Option D

Question No. 05
To pump water from a water reservoir 3 m deep and maximum water level at 135 m, a pump is
installed to lift water up to R.L. 175 m at a constant rate of 36,00,000 litres per hour. If the length
of the pipe is 1506 m and f = 0.01, ignoring other minor losses and assuming the economical
diameter from Lea's formula D = 1.2 Q, the water horse power of the pump is
(A) 400
(B) 450
(C) 500
(D) 600
Answer: Option D

Question No. 06
Turbidity of raw water is a measure of
(A) Suspended solids
(B) Acidity of water
(C) B.O.D.
(D) None of these
Answer: Option A

Question No. 07
If the chosen diameter of a pipe, is less than the economical diameter
(A) Cost of pipe will be less
(B) Head loss will be high
(C) Cost of pumping will be more than saving
(D) All the above
Answer: Option D

Question No. 08
Pick up the correct statement from the following:
(A) The water level in a still well, represents the ground water table level
(B) The difference between water table level and the water level in a well after pumping, is
called depression head
(C) The surface of water table surrounding a well during pumping, forms a cone of depression
(D) All the above
Answer: Option D

Question No. 09
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 m
(B) 2.25 m
(C) 2.50 m
(D) 3.00 m
Answer: Option D

Question No. 10
Pick up the correct statement from the following:
(A) Water with hardness upto 75 ppm is considered soft
(B) Water with hardness more than 200 ppm is considered hard
(C) Water needed for laundries should contain hardness less than 75 ppm
(D) All the above
Answer: Option D

Question No. 11
In centrifugal pump installation,
(A) Pump is properly primed before starting
(B) The diameter of the pipe at inlet as well as at outlet, is kept smaller than the delivery pipe
(C) The motor may burn out if it is started with empty delivery pipe and with open gate valve
(D) All the above
Answer: Option D

Question No. 12
While determining the yield of open wells by the pumping test
(A) Velocity of recharging water, increases with depression head
(B) Depression head resulting at critical velocity, is called critical depression head
(C) Working head is generally limited to
(D) Maximum safe yield of an open well, is expected at critical depression head
Answer: Option D

Question No. 13
The process of passing water through beds of granular materials, is called
(A) Screening
(B) Sedimentation
(C) Filtration
(D) None of these
Answer: Option C

Question No. 14
For the prediction of future population of a city, the factor to be considered, is
(A) Births
(B) Deaths
(C) Migrants
(D) All the above
Answer: Option D

Question No. 15
Mathamoglobinemia or blue baby disease is caused due to
(A) Chlorides
(B) Nitrites
(C) Nitrates
(D) Sulphides
Answer: Option C

Question No. 16
To control the growth of algae in reservoirs, the compound which is used, is
(A) Bleaching powder
(B) Copper sulphate
(C) Lime solution
(D) Alum solution
Answer: Option B

Question No. 17
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) 55,000
(B) 60,500
(C) 66,500
(D) 72,500
Answer: Option C

Question No. 18
A pressure conduit laid underground, 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
Answer: Option C

Question No. 19
The bacterias which require free oxygen for their survival, are called
(A) Aerobic bacterias
(B) Anaerobic bacterias
(C) Facultative bacteria
(D) None of these
Answer: Option A

Question No. 20
Gravity conduits are generally in the form of
(A) Canals
(B) Flumes
(C) Aqueduct
(D) All the above
Answer: Option D

Question No. 21
The main disadvantage of hard water, is
(A) Greater soap consumption
(B) Scaling of boilers
(C) Corrosion and incrustation of pipes
(D) All the above
Answer: Option D

Question No. 22
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 centigrade and K is a constant, is known
(A) Justin's formula
(B) Khosla's formula
(C) English formula
(D) Vermule's formula
Answer: Option B

Question No. 23
The bed slope in slow sand filters, is generally kept
(A) 1 in 50
(B) 1 in 75
(C) 1 in 100
(D) 1 : 200
Answer: Option C

Question No. 24
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) 0.0033
(B) 0.0044
(C) 0.0055
(D) 0.0066
Answer: Option C

Question No. 25
Perched aquifers are generally found
(A) On the surface of the ground
(B) Below the surface of the ground but above water table
(C) Below the water table
(D) All the above
Answer: Option B

Question No. 26
Pick up the incorrect statement from the following:
(A) The pH value of water indicates the logarithm of reciprocal of hydrogen ion concentration in
water
(B) Higher value of pH means lower hydrogen ion concentration
(C) Lower value of pH means higher hydrogen ion contraction
(D) Lower value of pH gives alkaline solution
Answer: Option D

Question No. 27
Mostly used coagulant, is
(A) Chlorine
(B) Alum
(C) Lime
(D) Bleaching powder
Answer: Option B

Question No. 28
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)
Answer: Option A

Question No. 29
Suction lift of a pump depends upon
(A) Atmospheric pressure
(B) Water temperature
(C) Velocity of water in suction pipe
(D) All the above
Answer: Option D

Question No. 30
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
Answer: Option B

Question No. 31
'Shrouding' is essentially provided in
(A) Strainer type wells
(B) Cavity type wells
(C) Slotted type well
(D) All the above
Answer: Option C

Question No. 32
The maximum permissible hardness for public supplies is
(A) 95 mg/litre
(B) 105 mg/litre
(C) 115 mg/litre
(D) 125 mg/litre
Answer: Option C

Question No. 33
Time of concentration
(A) Is the time taken, for precipitation
(B) Duration of rainfall
(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
Answer: Option D

Question No. 34
The chlorine supply cylinders are generally kept at 38°C to 40°C to prevent
(A) Conversion into crystals
(B) It from burning
(C) It from explosion
(D) None of these
Answer: Option A

Question No. 35
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 = 0.22 Q
(B) D = 1.22 Q
(C) D = 2.22 Q
(D) D = 3.22 Q
Answer: Option B

Question No. 36
An earth formation which, although porous and capable of absorbing water does not provide an
appreciable supply to wells, is known as
(A) Aquifer
(B) Aquiclude
(C) Aquifuge
(D) None of these
Answer: Option B

Question No. 37
Property of earth to allow water to pass through it, is known as
(A) Perviousness
(B) Porosity
(C) Permeability
(D) Transmissibility
Answer: Option A

Question No. 38
Plain chlorination is used for water
(A) Obtained from clear lakes
(B) Consumed during emergencies
(C) Supplies to armies during war
(D) All the above
Answer: Option D

Question No. 39
A city supply includes
(A) Domestic water demand
(B) Industrial and commercial water demands
(C) Demand for public uses and fire
(D) All the above
Answer: Option D

Question No. 40
The pH value of water is kept slightly less than 7 so that hydrochloride ions may combine with
ammonia ions to form
(A) Mono-chloramine (NHCl)
(B) Di-chloramine (NH2Cl)
(C) Nitrogen tri-chloramine (NCl3)
(D) All the above
Answer: Option D

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