# Practice Test: Question Set - 05

1. Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of
(A) 39.2%
(B) 49.2%
(C) 68.8%
(D) 84.8%

2. Overall 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

3. Which of the following pump is generally used to pump highly viscous fluid?
(A) Centrifugal pump
(B) Reciprocating pump
(C) Air lift pump
(D) Screw pump

4. High specific speed of turbine implies it is
(A) Propeller turbine
(B) Francis turbine
(C) Impulse turbine
(D) None of the above

5. In a reciprocating pump, air vessels are used to
(A) Smoothen the flow

6. The specific speed of a turbine is given by the equation
(A) N√P / H3/2
(B) N√P / H²
(C) N√P / H5/4
(D) N√P / H3

7. 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

8. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as
(A) Normal speed
(B) Unit speed
(C) Specific speed
(D) None of these

9. Francis turbine is best suited for
(A) Medium head application from 24 to 180 m
(B) Low head installation up to 30 m
(C) High head installation above 180 m

10. Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and Î·o = Overall efficiency of the pump)
(A) (w Hm) / (Q × Î·o)
(B) (w Hm Q) / Î·o
(C) (w Q) / (Hm × Î·o)
(D) (w Q  Î·o) / Hm

11. By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is
(A) 39.2%
(B) 48.8%
(C) 84.8%
(D) 88.4%

(B) Absolute velocity
(D) Flow

13. The maximum hydraulic efficiency of an impulse turbine is (where Ï† = Angle of blade tip at outlet)
(A) (1 + cos Ï†)/2
(B) (1 - cos Ï†)/2
(C) (1 + sin Ï†)/2
(D) (1 - sin Ï†)/2

14. The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is _______ of the jet velocity,
(A) One-fourth
(B) One-half
(C) Three-fourth
(D) Double

15. A hydraulic intensifier normally consists of
(A) Two cylinders, two rams and a storage device
(B) A cylinder and a ram
(C) Two coaxial rams and two cylinders
(D) A cylinder, a piston, storage tank and control valve

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