Questions and answers for exam Preparation

MCQs

Total Questions : 304 | Page 3 of 31 pages

Question 21. Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.

diameter
square of diameter
cube of diameter
fourth power of diameter

Discuss Question

Answer: Option D. -> fourth power of diameter
Answer: (d).fourth power of diameter

Question 22. The mechanical efficiency of an impulse turbine is

ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
ratio of the actual work available at the turbine to the energy imparted to the wheel
ratio of the Work done on the wheel to the energy of the jet
none of the above

Discuss Question

Answer: Option B. -> ratio of the actual work available at the turbine to the energy imparted to the wheel
Answer: (b).ratio of the actual work available at the turbine to the energy imparted to the wheel

Question 23. In a Kaplan turbine runner, the number of blades are generally between

2 to 4
4 to 8
8 to l6
16 to 24

Discuss Question

Answer: Option B. -> 4 to 8
Answer: (b).4 to 8

Question 24. The overshot water wheels are those in which the wheel runs entirely by the __________ of water.

weight
impulse
Can't say
None of these

Discuss Question

Answer: Option A. -> weight
Answer: (a).weight

Question 25. If Hg is the gross or total head and hf is the head lost due to friction, then net or effective head (H) is given by

H = Hg/hf
H = Hg x hf
H = Hg + hf
H = Hg - hf

Discuss Question

Answer: Option D. -> H = Hg - hf
Answer: (d).H = Hg - hf

Question 26. In a reaction turbine, the pressure head of water, while flowing over the vanes, is converted into kinetic head before leaving the wheel.

Agree
Disagree
Can't say
None of these

Discuss Question

Answer: Option B. -> Disagree
Answer: (b).Disagree

Question 27. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as

normal speed
unit speed
specific speed
none of these

Discuss Question

Answer: Option C. -> specific speed
Answer: (c).specific speed

Question 28. For centrifugal pump impeller, the maximum value of the vane exit angle is

10° to 15°
15° to 20°
20° to 25°
25° to 30°

Discuss Question

Answer: Option C. -> 20° to 25°
Answer: (c).20° to 25°

Question 29. Manometric head, in case of a centrifugal pump, is equal to

Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe
Workdone per kN of water - Losses within the impeller
Energy per kN at outlet of impeller - Energy per kN at inlet of impeller
all of the above

Discuss Question

Answer: Option D. -> all of the above
Answer: (d).all of the above

Question 30. The force exerted by a jet of water (in a direction normal to flow) impinging on a fixed plate inclined at an angle θ with the jet is