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
By boiling water, hardness can be removed if it is due to_________________?
(A) calcium sulphate
(B) magnesium sulphate
(C) calcium nitrate
(D) calcium bicarbonate
(D) none of these
Asbestos pipes are ______________?
(A) light in weight and easy to transport
(B) highly resistant to corrosion
(C) high flexible to accommodate deflection upto 12°
(D) very much smooth and hydraulically efficient
(D) all the above
In distribution pipes, drain valves are provided at_______________?
(A) lower point
(B) higher point
(C) junction points
(D) any where
Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be________________?
(A) nil
(B) 5
(C) 10
(D) 15
(D) 20
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
Average annual rainfall at any station is the average of annual rainfall over a period of________________?
(A) 7 years
(B) 14 years
(C) 21 years
(D) 28 years
(D) 35 years
Disinfection of drinking water, is done to remove_________________?
(A) odour
(B) bacterias
(C) turbidity
(D) colour
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) 2.75 m
(D) 3.00 m
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