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
View Answer
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
View Answer
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
View Answer
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.
4. The difference in the total head of the pump is called _______
a) Manometric head
b) Euler head
c) Pressure head
d) Shaft head
View Answer
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 _______
a) Manometric head
b) Euler head
c) Pressure head
d) Shaft head
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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
View Answer
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.
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