Hydraulic Machines-Fluid Machineries - Set 08 - ObjectiveBooks

Practice Test: Question Set - 08

1. Which of the following statement is correct as regard to water wheels?
(A) They have slow speeds
(B) They are suitable even for low water heads
(C) They give constant efficiency, even if the discharge is not constant
(D) All of the above

2. The unit power developed by a turbine is (where P = Power developed by the turbine under a head of water (H).
(A) P/ √H
(B) P/ H
(C) P/ H3/2
(D) P/ H²

3. Runaway speed of a hydraulic turbine is
(A) Full load speed
(B) The speed at which turbine runner will be damaged
(C) The speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open
(D) The speed corresponding to maximum overload permissible

4. Which type of the pump is different from others in the same group?
(A) Screw pump
(B) Gear pump
(C) Cam and piston pump
(D) Plunger pump

5. The specific speed of a centrifugal pump, delivering 750 liters of water per second against a head of 15 meters at 725 r.p.m., is
(A) 24.8 r.p.m.
(B) 48.2 r.p.m
(C) 82.4 r.p.m.
(D) 248 r.p.m

6. 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

7. In an inward flow reaction turbine
(A) The water flows parallel to the axis of the wheel
(B) The water enters at the center of the wheel and then flows towards the outer periphery of the wheel
(C) The water enters the wheel at the outer periphery and then flows towards the center of the wheel
(D) The flow of water is partly radial and partly axial

8. In impulse Turbine, energy available at the inlet is in the form of
(A) Potential Energy
(B) Strain Energy
(C) Kinetic energy
(D) None of these

9. A Pelton wheel develops 1750 kW under a head of 100 meters while running at 200 r.p.m. and discharging 2500 liters of water per second. The unit discharge of wheel is
(A) 0.25 m3/s
(B) 0.5 m3/s
(C) 1.5 m3/s
(D) 2.5 m3/s

10. Power required to drive a centrifugal pump is directly proportional to _________ of its impeller.
(A) Diameter
(B) Square of diameter
(C) Cube of diameter
(D) Fourth power of diameter

11. Which of the following statement is wrong?
(A) The reaction turbines are used for low head and high discharge
(B) The angle of taper on draft tube is less than 8°
(C) An impulse turbine is generally fitted slightly above the tail race
(D) A Francis turbine is an impulse turbine

12. Discharge of a centrifugal pump is
(A) Directly proportional to diameter of its impeller
(B) Inversely proportional to diameter of its impeller
(C) Directly proportional to (diameter)² of its impeller
(D) Inversely proportional to (diameter)² of its impeller

13. The speed of a turbine runner is
(A) Directly proportional to H1/2
(B) Inversely proportional to H1/2
(C) Directly proportional to H3/2
(D) Inversely proportional to H3/2

14. In a reaction turbine, the draft tube is used
(A) To run the turbine full
(B) To prevent air to enter the turbine
(C) To increase the head of water by an amount equal to the height of the runner outlet above the tail race
(D) To transport water to downstream

15. Slip of a reciprocating pump is defined as the
(A) Ratio of actual discharge to the theoretical discharge
(B) Sum of actual discharge and the theoretical discharge
(C) Difference of theoretical discharge and the actual discharge
(D) Product of theoretical discharge and the actual discharge

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