# Hydraulic Machines Questions and Answers – Work done by Centrifugal Pump

This set of Hydraulic Machines MCQs focuses on “Work done by Centrifugal Pump”.

1. The fluid gains _________ while passing through the impeller.
a) Velocity
b) Pressure
c) Temperature
d) Velocity and pressure

Explanation: The fluid gains both velocity and pressure while passing through the impeller. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors.

2. What is the shape of the diffuser in the centrifugal pump?
a) Round
b) Dough nut
c) Rectangle
d) Cylindrical

Explanation: The shape of the diffuser passing present in the centrifugal pump is doughnut shaped. It is made into that shape as it allows the device to scroll up and down. Due to this, the casing decelerates the flow.

3. When the casing in a centrifugal pump decelerates the flow, what increases?
a) Pressure
b) Temperature
c) Volume
d) Flow rate

Explanation: When the casing in a centrifugal pump decelerates the flow, pressure in the turbine increases. The diffuser helps this happen. The shape of the diffuser passing present in the centrifugal pump is doughnut shaped.

4. The velocity imparted by the impeller is converted into _________
a) Pressure energy
b) Kinetic energy
c) Momentum
d) Potential energy

Explanation: The velocity imparted by the impeller is converted into pressure energy. It is in accordance with the Newtons second law.

5. The consequence of Newtons second law is_________
a) Conservation of angular momentum
b) Conservation of mass
c) Conservation of potential energy
d) Conservation of kinetic energy

Explanation: The consequence of Newtons second law is the conservation of angular momentum. This, in accordance with newtons second law, provides the basic details to define parameters in the centrifugal pump.
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6. Change of angular momentum is equal to ________
a) Sum of external moments
b) Sum of their potential energies
c) Sum of their kinetic energies
d) Sum of their pressures

Explanation: Change of angular momentum is equal to Sum of external moments. This is in accordance with Newtons second law. The consequence of Newtons second law is the conservation of angular momentum.

7. Euler developed the head pressure equation in centrifugal pumps.
a) True
b) False

Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps transport fluids by converting rotational Kinetic energy to hydrodynamic energy. Euler developed the head pressure equation in centrifugal pumps.

8. What is a major advantage of centrifugal pump?
a) Cost
b) Simple in construction
c) Efficiency
d) Pump parameters

Explanation: The major advantage of the centrifugal pump is that it has got a simple construction when compared to other types of centrifugal pumps.

9. ‘Ht’ means _______

Explanation: ‘Ht’ in the context of centrifugal pump means theory head pressure. It is used in a centrifugal pump equation that was derived by Euler. Euler developed the head pressure equation in centrifugal pumps.

10. Centrifugal pumps are used to transport ________
a) Pressure
b) Speed
c) Power
d) Fluid

Explanation: Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies. Centrifugal pumps are a sub class of dynamic axisymmetric work absorbing turbomachinery.

11. Different velocities in a centrifugal pump are determined by using ________
a) Velocity triangle
b) Reynolds number
c) Froude number
d) Overall efficiency

Explanation: Different velocities in a centrifugal pump are determined by using velocity triangle. This is an important triangle that determines the way the pump works.

12. Due to its impeller action, centrifugal pumps can cover a wide range of fluid pump applications.
a) True
b) False

Explanation: Due to its impeller action, centrifugal pumps can cover a wide range of fluid pump applications. Thus, the impeller action plays an important role.

13. With the increase in the input power, efficiency _______
a) Increases
b) Decreases
c) Same
d) Independent

Explanation: With the increase in the input power, efficiency decreases. As the input power is inversely proportional to the efficiency of the pump.

14. What is unit of standard acceleration?
a) kg/m
b) kg/s
c) kg/m3
d) N/m

Explanation: The unit of standard acceleration of the centrifugal pump is kg/m3. It is denoted as g. It is also called as the acceleration due to gravity.

15. What does PSP stand for?
a) Pump start procedure
b) Positive start pump
c) Pump start pointer
d) Positive start pointer

Explanation: PSP stands for Pump start procedure. It is the basic method to start the pump by lining up the pump valves in a sequence by ensuring that the drain valve is closed.

Sanfoundry Global Education & Learning Series – Hydraulic Machines.

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