Hydraulic Machines-Fluid Machineries - Set 07 - ObjectiveBooks

# Practice Test: Question Set - 07

1. Which of the following pump is preferred for flood control and irrigation applications?
(A) Centrifugal pump
(B) Axial flow pump
(C) Mixed flow pump
(D) Reciprocating pump

2. Multistage centrifugal pumps are used to
(A) Give high discharge
(C) Pump viscous fluids
(D) All of these

3. Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of
(A) High initial and maintenance cost
(B) Lower discharge
(C) Lower speed of operation
(D) Necessity of air vessel

4. The efficiency of a Pelton wheel working under constant head ________ with the increase in power.
(A) Remain same
(B) Increases
(C) Decreases
(D) None of these

5. The discharge through a reaction turbine __________ with the increase in unit speed.
(A) Decreases
(B) Increases
(C) Remain same
(D) None of these

6. 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

7. A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is
(A) 0.26
(B) 0.36
(C) 0.46
(D) 0.56

8. The specific speed of a hydraulic turbine depends upon
(A) Speed and power developed
(B) Discharge and power developed
(C) Speed and head of water
(D) Speed, power developed and head of water

9. Head developed by a centrifugal pump depends on
(A) Impeller diameter
(B) Speed
(C) Fluid density
(D) Both (A) and (B) above

10. If the ratio's of the corresponding forces acting at corresponding points 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

11. 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 speed of the wheel is
(A) 10 r.p.m.
(B) 20 r.p.m.
(C) 40 r.p.m.
(D) 80 r.p.m.

12. Centrifugal pump is started with its delivery valve
(A) Kept fully closed
(B) Kept fully open
(C) Irrespective of any position
(D) Kept 50% open

13. The cavitation in reaction turbines is avoided, to a great extent by
(A) Installing the turbine below the tail race level
(B) Using stainless steel runner of the turbine
(C) Providing highly polished blades to the runner
(D) All of the above

14. In a centrifugal pump casing, the flow of water leaving the impeller, is
(A) Rectilinear flow
(C) Free vortex motion
(D) Forced vortex

15. A hydraulic accumulator is a device used to store _________ energy which may be supplied to a machine later on.
(A) Strain
(B) Pressure
(C) Kinetic
(D) None of these

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