# Water Supply Engineering MCQ Questions & Answers

Water Supply Engineering MCQs : This section focuses on the "Water Supply Engineering". These Multiple Choice Questions (MCQs) should be practiced to improve the Water Supply Engineering skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

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

Question 2

According to IS : 1172-1963, a minimum of 135 litres of water capita per day, is required for

A. Boarding schools
B. Nurses home and medical quarters
C. hostels
D. all the above.

Question 3

Aeration of water is done to remove

A. odour
B. colour
C. bacterias
D. hardness

Question 4

Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be

A. nil
B. 5
C. 10
D. 15

Question 5

By boiling water, hardness can be removed if it is due to

A. calcium sulphate
B. magnesium sulphate
C. calcium nitrate
D. calcium bicarbonate

Question 6

Corrosion of well pipes may not be reduced by

A. reducing the draw down and the pumping rate
B. reducing the flow velocity
C. using thicker pipes
D. using screens having larger area of openings

Question 7

Disinfection of drinking water, is done to remove

A. odour
B. bacterias
C. turbidity
D. colour.

Question 8

Distribution mains of any water supply, is normally designed for its average daily requirement

A. 100%
B. 150%
C. 200%
D. 225%.

Question 9

Economic height of a dam is the height corresponding to which

A. cost of the dam per unit of storage is minimum
B. amount of silting is less
C. cost of dam per unit storage is maximum
D. free board provided is least

Question 10

For determining the velocity of flow of underground water, the most commonly used non-empirical formula is

A. Darcy's formula
B. Slichter's formula
C. Hazen's formula
D. Lacy's formula.

Question 11

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.

Question 12

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 the above.

Question 13

In distribution pipes, drain valves are provided at

A. lower point
B. higher point
C. junction points
D. any where.

Question 14

In pressure supply mains, water hammer pressure is reduced by providing

A. sluice valves
B. air valves
C. pressure relief valves
D. none of the these.

Question 15

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.

Question 16

Manholes along the mains from the source to a city are provided at 500 m intervals in

A. steel pipes
B. R.C.C. pipes
C. hume steel pipes
D. all the above.

Question 17

Most commonly used pump for lifting water in water supply mains, is

A. axialflow pump
B. reciprocating pump
C. rotary type pump
D. centrifugal pumps

Question 18

Pick up the correct statement from the following :

A. Detention period for plain sedimentation tanks ranges between 4 to 8 hours
B. Detention period for sedimentation tanks, using coagulants usually ranges between 2 to 4 hours
C. The horizontally flow velocity in sedimentation tanks, is generally limited to 0.3 m/minute
D. All the above.

Question 19

Pick up the incorrect statement from the following regarding fire hydrants

A. Fire hydrants are fitted in water mains at 100 m to 150 m apart at fire
B. The minimum water pressure hydrants, is kept 1.5 kg/cm2
C. The water at pressure 1 to 1.5 kg/cm2 is made available for 4 to 5 hours for constant use
D. None of these.

Question 20

Pick up the incorrect statement from the following. The underground sources of water, is from

A. wells
B. springs
C. infiltration wells
D. storage reservoirs

Question 21

Sunlight

A. helps growth of bacterias
B. impedes growth of algae
C. increases dissolved oxygen content
D. reduces turbidity.

Question 22

Surge tanks are used

A. for storage water
B. to increase the velocity in a pipeline
C. as overflow valves
D. to guard against water hammer.

Question 23

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.

Question 24

The maximum permissible nitrites in public water supplies, is

A. Nil
B. 0.5 P.P.M.
C. 1.0. P.P.M.
D. 1.5 P.P.M.

Question 25

The population growth curve is

A. S-shaped curve
B. parabolic curve
C. circular curve
D. straight line

Question 26

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. 1500 m
B. 1505 m
C. 1475 m
D. 1485 m.

Question 27

The specific retention is least in case of

A. Clay
B. Sand
C. Silt
D. Coarse gravel.

Question 28

The transitional middle portion of a logistic curve follows

A. a geometric growth
B. a logarithmic growth
C. a first over curve
D. a constant rate.

Question 29

The yield of a rapid gravity filter as compared to that of slow sand filter, is

A. 10 times
B. 15 times
C. 20 times
D. 30 times

Question 30

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.

Question 31

Turbidity of raw water is a measure of

A. suspended solids
B. acidity of water
C. B.O.D.
D. none of these.