Hydraulic Machines and Fluid Machineries Objective Questions with Answers - ObjectiveBooks

# Practice Test: Question Set - 12

1. Which of the following pump is successfully used for lifting water from deep wells?
(A) Centrifugal pump
(B) Reciprocating pump
(C) Jet pump
(D) Air lift pump

2. When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be
(A) Horizontal
(B) Nearly horizontal
(C) Steep
(D) First rise and then fall

3. The overall efficiency for a Pelton wheel lies between
(A) 0.50 to 0.65
(B) 0.65 to 0.75
(C) 0.75 to 0.85
(D) 0.85 to 0.90

4. The efficiency of a hydraulic press is given by (where W = Weight lifted by ram, P = Force applied on plunger, A = Area of ram, and a = Area of plunger)
(A) (W/p) × (A/a)
(B) (p/W) × (a/A)
(C) (W/p) × (a/A)
(D) (p/W) × (A/a)

5. In a centrifugal pump casing, the flow of water leaving the
(B) Axial
(C) Centrifugal
(D) Vortex

6. The unit discharge through the turbine is
(A) Q/√H
(B) Q/H
(C) Q/H3/2
(D) Q/H²

7. 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
(A) H = Hg/hf
(B) H = Hg × hf
(C) H = Hg + hf
(D) H = Hg - hf

8. Manometric head, in case of a centrifugal pump, is equal to
(A) 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
(B) Work-done per kN of water Losses within the impeller
(C) Energy per kN at outlet of impeller Energy per kN at inlet of impeller
(D) All of the above

9. In a Francis turbine runner, the numbers of blades are generally between
(A) 2 to 4
(B) 4 to 8
(C) 8 to 16
(D) 16 to 24

10. The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) is
(A) ηh = ηo × ηm
(B) ηm = ηm × ηh
(C) ηo = ηh × ηm
(D) None of these

11. The ratio of actual work available at the turbine to the energy imparted to the wheel is known as ________ efficiency.
(A) Hydraulic
(B) Mechanical
(C) Overall
(D) None of these

12. The force exerted by a jet of water impinging normally on a plate which due to the impact of jet, moves in the direction of jet with a velocity v is
(A) [wa (V - v)]/2g
(B) [wa (V - v)]/g
(C) [wa (V - v)²]/2g
(D) [wa (V - v²)]/g

13. The number of buckets on the periphery of a Pelton wheel is given by
(A) (D/2d) + 5
(B) (D/2d) + 10
(C) (D/2d) + 15
(D) (D/2d) + 20

14. The cavitation in a hydraulic machine
(A) Causes noise and vibration of various parts
(B) Reduces the discharge of a turbine
(C) Causes sudden drop in power output and efficiency
(D) All of the above

15. Geometric 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

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