FLUID MECHANICS MCQ SET 6
Q1. The main function of a centrifugal pump is to:
A) Convert hydraulic energy into mechanical energy
B) Convert mechanical energy into hydraulic energy
C) Increase temperature of fluid
D) Reduce velocity of fluid
Answer: B) Convert mechanical energy into hydraulic energy
Explanation: A centrifugal pump converts mechanical energy from a motor into fluid energy to lift or move liquids.
Q2. The efficiency of a centrifugal pump is maximum when its blades are:
A) Forward curved
B) Backward curved
C) Radial
D) Straight
Answer: B) Backward curved
Explanation: Backward-curved blades offer smooth flow and higher efficiency compared to other designs.
Q3. The specific speed of a pump indicates:
A) Type of pump
B) Flow characteristics
C) Shape of impeller
D) All of the above
Answer: D) All of the above
Explanation: Specific speed helps in selecting the right type of pump (radial, mixed, or axial flow).
Q4. Cavitation in pumps occurs when:
A) Pressure falls below vapor pressure
B) Flow velocity is high
C) Temperature increases
D) Head loss increases
Answer: A) Pressure falls below vapor pressure
Explanation: Cavitation occurs when local pressure drops below vapor pressure, forming vapor bubbles that damage the pump.
Q5. The best remedy to avoid cavitation is:
A) Reduce speed of pump
B) Increase suction head
C) Increase Net Positive Suction Head (NPSH)
D) Decrease delivery head
Answer: C) Increase Net Positive Suction Head (NPSH)
Explanation: Increasing NPSH prevents pressure drop below vapor pressure, thus avoiding cavitation.
Q6. In a reciprocating pump, the fluid is moved by:
A) Centrifugal action
B) Pressure difference
C) Reciprocating piston motion
D) Gravity
Answer: C) Reciprocating piston motion
Explanation: A reciprocating pump uses a piston or plunger to push and pull the liquid inside the cylinder.
Q7. Slip in a reciprocating pump is defined as:
A) Actual discharge โ Theoretical discharge
B) Theoretical discharge โ Actual discharge
C) Total head / Power
D) None
Answer: B) Theoretical discharge โ Actual discharge
Explanation: Slip shows the difference between ideal and actual flow, mainly due to leakage or clearance losses.
Q8. A turbine converts:
A) Heat energy into pressure energy
B) Mechanical energy into fluid energy
C) Fluid energy into mechanical energy
D) Pressure energy into heat
Answer: C) Fluid energy into mechanical energy
Explanation: Turbines extract energy from fluids and convert it into mechanical rotation to drive generators.
Q9. The unit of power of a turbine is:
A) Watt
B) Joule
C) Pascal
D) Newton
Answer: A) Watt
Explanation: Power output of turbines is expressed in Watts (or kilowatts), where 1 W = 1 J/s.
Q10. The Pelton wheel is a type of:
A) Reaction turbine
B) Impulse turbine
C) Mixed flow turbine
D) Axial flow turbine
Answer: B) Impulse turbine
Explanation: The Pelton wheel uses high-velocity jets striking buckets to produce torque โ pure impulse action.
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