# Hydraulic Machines-Fluid Machineries – Set 04

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## Q1. If the ratios of all the corresponding linear dimensions are equal, then the model and the prototype are said to have

(A) Geometric similarity
(B) Kinematic similarity
(C) Dynamic similarity
(D) None of these

## Q2. Kinematic similarity is said to exist between the model and the prototype, if both of them

(A) Have identical velocities
(B) Are equal in size and shape
(C) Are identical in shape, but differ only in size
(D) Have identical forces

(A) 0.15 to 0.3
(B) 0.4 to 0.5
(C) 0.6 to 0.9
(D) 1 to 1.5

(A) Double
(B) Three times
(C) Four times
(D) Five times

(A) N√P / H3/2
(B) N√P / H²
(C) N√P / H5/4
(D) N√P / H3

## Q6. The overall efficiency of a reaction turbine is the ratio of

(A) Power produced by the turbine to the energy actually supplied by the turbine
(B) Actual work available at the turbine to the energy imparted to the wheel
(C) Work-done on the wheel to the energy (or head of water) actually supplied to the turbine
(D) None of the above

Answer: (A) Power produced by the turbine to the energy actually supplied by the turbine

## Q7. Axial flow pump is started with its delivery valve

(A) Kept fully closed
(B) Kept fully open
(C) Irrespective of any position
(D) Kept 50% open

## Q8. When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be

(A) Horizontal
(B) Nearly horizontal
(C) Steep
(D) First rise and then fall

## Q9. Delivery head of a centrifugal pump is

(A) Directly proportional to N
(B) Inversely proportional to N
(C) Directly proportional to N²
(D) Inversely proportional to N²

Answer: (C) Directly proportional to N²

## Q10. Mechanical efficiency of a centrifugal pump is the ratio of

(A) Energy available at the impeller to the energy supplied to the pump by the prime mover
(B) Actual work-done by the pump to the energy supplied to the pump by the prime mover
(C) Energy supplied to the pump to the energy available at the impeller
(D) Manometric head to the energy supplied by the impeller per kN of water

Answer: (A) Energy available at the impeller to the energy supplied to the pump by the prime mover

(A) 39.2%
(B) 48.8%
(C) 84.8%
(D) 88.4%

(A) Q/√H
(B) Q/H
(C) Q/H3/2
(D) Q/H²

(A) 10-15°
(B) 20-25°
(C) 30-40°
(D) 50-60°

## Q14. For very high discharge at low pressure such as for flood control and irrigation applications, following type of pump is preferred

(A) Centrifugal
(B) Axial flow
(C) Reciprocating
(D) Mixed flow

## Q15. The specific speed of turbine is defined as the speed of a unit

(A) Of such a size that it delivers unit discharge at unit head
(B) Of such a size that it delivers unit discharge at unit power
(C) Of such a size that it requires unit power per unit head
(D) Of such a size that it produces unit horse power with unit head

Answer: (D) Of such a size that it produces unit horse power with unit head

## Q16. Which place in hydraulic turbine is most susceptible for cavitations?

(A) Inlet of draft rube
(D) Penstock

Answer: (A) Inlet of draft rube

## Q17. In order to avoid cavitation in centrifugal pumps

(A) The suction pressure should be high
(B) The delivery pressure should be high
(C) The suction pressure should be low
(D) The delivery pressure should be low

Answer: (A) The suction pressure should be high

## Q18. 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

(A) (waV/2g) × sin θ
(B) (waV/g) × sin θ
(C) (waV²/2g) × sin 2θ
(D) (waV²/g) × sin θ

Answer: (C) (waV²/2g) × sin 2θ

(A) 0.26
(B) 0.36
(C) 0.46
(D) 0.56