# Hydraulic Machines Questions and Answers – Heads and Efficiencies in Centrifugal Pumps

«
»

This set of Hydraulic Machines Multiple Choice Questions & Answers (MCQs) focuses on “Heads and Efficiencies in Centrifugal Pumps”.

1. What is the unit of flow rate?
a) kg.m
b) kg/m
c) m3/s
d) /s

Explanation: The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.

2. With the increase in the flow rate, efficiency ______
a) Decreases
b) Increases
c) Remains same
d) Independent

Explanation: With the increase in the flow rate, efficiency increases. The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.

3. Pump efficiency is defined as the ratio of ___________
a) Pressure to temperature
b) Temperature to pressure
c) Water horsepower to pump horsepower
d) Pump horse power to water horse power

Explanation: Pump efficiency is defined as the ratio of water horsepower to the pump horsepower. The unit of flow rate in a centrifugal pump is m3/s. It is denoted as ‘Q’. It plays an important role to determine the efficiency of the pump.
Note: Join free Sanfoundry classes at Telegram or Youtube

4. The difference in the total head of the pump is called _______

Explanation: The difference in the total head of the pump is called manometric head. Centrifugal pump is a turbomachinery. Turbomachines are machines that transfer energy between a rotor and a fluid, including both turbines and compressors.

5. The ratio of manometric head to the work head is called _______

Explanation: The ratio of manometric head to the work head is called Euler head. It is also called as manometric efficiency.

6. What is the unit of energy head?
a) m
b) m/s
c) m3/s
d) /s

Explanation: The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.

7. With the increase in energy head, efficiency ________
a) Decreases
b) Increases
c) Remains same
d) Independent

Explanation: With the increase in energy head, efficiency increases. Since energy is directly proportional to the efficiency of the turbine. The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.

8. The head added by the pump is a sum of _________
a) Pressure
b) Static lift
c) Volume
d) Flow rate

Explanation: The head added by the pump is a sum of static lift. With the increase in energy head, efficiency increases. Since energy is directly proportional to the efficiency of the turbine. The unit of energy head is meter. The energy head is denoted as ‘H’. It plays an important role to determine the efficiency of the pump.

9. Power is most commonly expressed as ________
a) m
b) kW
c) m3/s
d) /s

Explanation: Power is most commonly expressed as kilo watts. One kilo watts is equal to 0.746 horse power. It plays an important role in determining the efficiency of the turbine.

10. PHE stands for __________
a) Pump Hydraulic efficiency
b) Pressure Hydraulic efficiency
c) Power Hydraulic efficiency
d) Pump hydraulic engine

Explanation: PHE stands for Pump hydraulic efficiency. Centrifugal pumps are used to transport fluids. They transport fluids by conversion of energies.

11. Vertical centrifugal pumps are also called as cantilever pumps.
a) True
b) False

Explanation: Vertical centrifugal pumps are also called as cantilever pumps. 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.

12. With increase in power, the efficiency_________
a) Decreases
b) Increases
c) Remains 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.

13. Vertical pumps utilize unique shaft and bearing support configuration.
a) True
b) False

Explanation: Vertical pumps utilize unique shaft and bearing support configuration. It allows them to hang in the sump while the bearings are outside the sump. Thus, it is a true.

14. Which among the following is used in mineral industries?
a) Vertical pumps
b) Horizontal pumps
c) Froth pumps
d) Multistage pumps

Explanation: In the mineral industries, we use froth pumps to extract oil sand. Froth is generated to separate rich minerals.

Sanfoundry Global Education & Learning Series – Hydraulic Machines.

To practice all areas of Hydraulic Machines, here is complete set of 1000+ Multiple Choice Questions and Answers.