Question19:-A device installed in a drainage system to prevent reverse flow is .....
A:-back water valve
B:-back flow preventer
C:-back siphonage
D:-back vent pipe
Correct Answer:- Option-A
Question20:-In metric micro meters what is the pitch of the spindle thread

D:-0.01 mm

Correct Answer:- Option-B
Question21:-What is the term generally employed for a piece of pipe which is threaded on both ends and less than 12 inches
long?

D:-plugs
Correct Answer:- Option-A
Question22:-Pipe wrench is used for pipes of diameter.....
A:-less than 15 mm
B:-more than 150 mm
C:-50 mm to 150 mm
D:-15 mm to 50 mm
Correct Answer:- Option-D
Question23:-If the globe valve begins to leak between the packing nut and valve steam
A:-gland nut to be replaced
B:-packing to be replaced
C:-valve steam to be replaced
D:-Bonnet to be replaced
Correct Answer:- Option-B
Question24:-the lower most level or surface of a sewer is known as .....
കാസ
B:-bedding
C:-benching
D:-drain
Correct Answer:- Option-A
Question25:-What process is used to remove permanent hardness in water .....
A:-purification process
B:-coagulation process
C:-base exchange process
D:-sedimentation process
Correct Answer:- Option-C
Question26:-Dug wells are also known as .....
A:-draw wells
B:-tube wells
C:-driven wells
D:-artesian wells
Correct Answer:- Option-A
Question27:-What should be done to remove tapped air in centrifugal pump .....
A:-packing
B:-washing
C:-use booster pump
D:-priming
Correct Answer:- Option-D
Question28:-What is provided in elevated storage reservoir for circulation of air .....
A:-manhole
B:-ventilator
C:-float gauge