QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025/2026 Q&A | INSTANT DOWNLOAD PDF
1. Which type of pump is most suitable for transferring clean water from a deep
well?
A. Centrifugal pump
B. Submersible pump
C. Positive displacement pump
D. Gear pump
Correct Answer: B. Submersible pump
Rationale: Submersible pumps are designed to be installed below the water
surface, making them ideal for deep wells.
2. What is the primary purpose of a pump’s check valve?
A. Increase pressure
B. Prevent backflow
C. Reduce noise
D. Regulate temperature
Correct Answer: B. Prevent backflow
Rationale: Check valves allow flow in one direction only, preventing reverse flow
that could damage the pump or system.
3. Which material is commonly used for pump impellers in potable water
systems?
A. Cast iron
B. Bronze
C. Plastic
D. Stainless steel
Correct Answer: B. Bronze
,Rationale: Bronze is corrosion-resistant and safe for potable water, making it a
standard choice for impellers.
4. When installing a pump, why is it important to align the pump and motor
shafts?
A. To improve aesthetic appeal
B. To prevent vibration and wear
C. To increase flow rate
D. To reduce noise
Correct Answer: B. To prevent vibration and wear
Rationale: Misalignment can cause premature bearing and seal failure due to
excessive vibration and stress.
5. Which type of pump is best for handling viscous fluids?
A. Centrifugal pump
B. Gear pump
C. Submersible pump
D. Vertical turbine pump
Correct Answer: B. Gear pump
Rationale: Gear pumps are positive displacement pumps designed for viscous
fluids, providing steady flow regardless of viscosity.
6. What is the main function of a pump seal?
A. Increase pressure
B. Prevent leakage
C. Reduce vibration
D. Regulate speed
Correct Answer: B. Prevent leakage
Rationale: Seals prevent the pumped fluid from leaking along the shaft,
maintaining efficiency and safety.
7. Which factor primarily affects pump efficiency?
A. Shaft color
B. Impeller diameter and speed
C. Pump brand
, D. Electrical cord length
Correct Answer: B. Impeller diameter and speed
Rationale: The pump’s design, impeller size, and speed determine the head, flow
rate, and overall efficiency.
8. For a centrifugal pump, what does the term “shut-off head” mean?
A. Maximum flow rate
B. Pressure when flow is zero
C. Minimum suction required
D. Pump vibration limit
Correct Answer: B. Pressure when flow is zero
Rationale: Shut-off head is the maximum head the pump can achieve when the
discharge valve is closed.
9. Which safety precaution is most important before servicing an electrical
pump?
A. Wear gloves
B. Shut off power supply
C. Drain all fluid
D. Lubricate bearings
Correct Answer: B. Shut off power supply
Rationale: Disconnecting power prevents accidental start-up, avoiding electrical
shock or injury.
10. Why is priming necessary for some pumps?
A. To lubricate the impeller
B. To remove air and allow proper suction
C. To test the motor
D. To adjust flow rate
Correct Answer: B. To remove air and allow proper suction
Rationale: Pumps that cannot self-prime must have air removed from the suction
line to operate efficiently.
11. What does NPSH stand for in pump terminology?
A. Nominal Pump Safety Head