Hydro Power Plant – 50 MCQs with Answers

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Q1. The efficiency of a modern hydro power plant is about:
A) 40–50%
B) 60–70%
C) 70–80%
D) 80–90%
Ans: D

Q2. Which of the following has the lowest operating cost?
A) Thermal plant
B) Nuclear plant
C) Hydro plant
D) Diesel plant
Ans: C

Q3. Kaplan turbine is a:
A) Impulse turbine
B) Reaction turbine
C) Mixed turbine
D) Steam turbine
Ans: B

Q4. Pelton wheel works under:
A) High head, low discharge
B) Low head, high discharge
C) Medium head, medium discharge
D) None of these
Ans: A

Q5. Francis turbine is suitable for:
A) Low head
B) Medium head
C) High head
D) Very high head
Ans: B

Q6. The specific speed of Kaplan turbine is about:
A) 10–30
B) 50–150
C) 200–800
D) 1000–2000
Ans: C

Q7. Run-of-river plants have:
A) No storage
B) Small storage
C) Large storage
D) Both A and B
Ans: A

Q8. The surge tank is used to:
A) Increase efficiency
B) Reduce water hammer
C) Store water
D) Reduce cavitation
Ans: B

Q9. In hydro power plants, cavitation is caused by:
A) High velocity
B) Low pressure
C) Air bubbles
D) All of the above
Ans: D

Q10. The load factor of a hydro station is generally:
A) Very low
B) Low
C) High
D) Unity
Ans: B

Q11. Which turbine is axial flow type?
A) Pelton
B) Kaplan
C) Francis
D) Turgo
Ans: B

Q12. Which turbine is radial flow type?
A) Pelton
B) Kaplan
C) Francis
D) Turgo
Ans: C

Q13. The water hammer effect is reduced by:
A) Tail race
B) Surge tank
C) Draft tube
D) Governor
Ans: B

Q14. The unit of specific speed of turbine is:
A) rpm
B) rad/sec
C) Dimensionless
D) m/s
Ans: C

Q15. The function of draft tube is:
A) Convert velocity head into pressure head
B) Reduce turbine speed
C) Increase turbine pressure
D) Store water
Ans: A

Q16. Turbine used for low head and high discharge:
A) Francis
B) Kaplan
C) Pelton
D) Turgo
Ans: B

Q17. Turbine used for medium head:
A) Francis
B) Pelton
C) Kaplan
D) None
Ans: A

Q18. Pelton wheel efficiency is about:
A) 50–60%
B) 70–80%
C) 85–90%
D) 95%
Ans: C

Q19. Tail race is the:
A) Water reservoir
B) Water exit of turbine
C) Water inlet of turbine
D) Surge chamber
Ans: B

Q20. The main disadvantage of hydro power plants is:
A) High operating cost
B) Fuel problem
C) Dependence on rainfall
D) Low efficiency
Ans: C

Q21. Run-of-river plants with pondage are suitable for:
A) Base load
B) Peak load
C) Standby
D) None
Ans: B

Q22. Storage type hydro plants are used for:
A) Peak load
B) Base load
C) Both A and B
D) Standby
Ans: C

Q23. Pumped storage plants are used for:
A) Energy storage
B) Base load
C) Load balancing
D) Both A and C
Ans: D

Q24. Hydraulic efficiency of a turbine is:
A) Power developed / Water energy supplied
B) Power developed / Shaft power
C) Shaft power / Water energy supplied
D) Power developed / Gross head
Ans: A

Q25. Kaplan turbine works on:
A) Tangential flow
B) Axial flow
C) Radial flow
D) Mixed flow
Ans: B

Q26. The governor in hydro turbine controls:
A) Water flow
B) Head
C) Tail race
D) Draft tube
Ans: A

Q27. The draft tube efficiency is about:
A) 50%
B) 70%
C) 85%
D) 100%
Ans: C

Q28. The range of head for Kaplan turbine is:
A) 2–20 m
B) 20–70 m
C) 70–300 m
D) 300–1000 m
Ans: A

Q29. The range of head for Francis turbine is:
A) 2–20 m
B) 20–200 m
C) 200–500 m
D) >500 m
Ans: B

Q30. The range of head for Pelton turbine is:
A) 2–20 m
B) 20–200 m
C) 200–2000 m
D) >3000 m
Ans: C

Q31. The specific speed of Pelton turbine is:
A) 10–30
B) 30–60
C) 60–100
D) 100–300
Ans: A

Q32. The maximum efficiency of Francis turbine is:
A) 70%
B) 80%
C) 85–90%
D) 95%
Ans: C

Q33. The cavitation in turbines occurs at:
A) Inlet
B) Runner
C) Draft tube exit
D) Guide vanes
Ans: C

Q34. The hydraulic turbine converts:
A) Pressure energy into mechanical energy
B) Kinetic energy into mechanical energy
C) Potential energy into mechanical energy
D) All of the above
Ans: D

Q35. Turgo impulse turbine is suitable for:
A) Low head
B) Medium head
C) High head
D) Both B and C
Ans: D

Q36. Main losses in hydro turbine are:
A) Hydraulic loss
B) Mechanical loss
C) Leakage loss
D) All of the above
Ans: D

Q37. Kaplan turbine blades are:
A) Fixed
B) Adjustable
C) Tangential
D) Radial
Ans: B

Q38. The unit of water power is:
A) kWh
B) HP
C) kW
D) Both B and C
Ans: D

Q39. The most efficient turbine is:
A) Pelton
B) Francis
C) Kaplan
D) All have same efficiency
Ans: C

Q40. Governing of turbine means:
A) Controlling head
B) Controlling flow
C) Controlling load
D) Both B and C
Ans: D

Q41. Which turbine has fixed runner blades?
A) Kaplan
B) Francis
C) Pelton
D) Turgo
Ans: C

Q42. Cavitation can be minimized by:
A) Increasing draft tube length
B) Maintaining suction head low
C) Using stainless steel blades
D) Both B and C
Ans: D

Q43. The velocity of water jet striking Pelton wheel is about:
A) 10–20 m/s
B) 20–30 m/s
C) 40–50 m/s
D) 60–80 m/s
Ans: D

Q44. Kaplan turbine is also known as:
A) Propeller turbine
B) Radial turbine
C) Impulse turbine
D) Jet turbine
Ans: A

Q45. Hydraulic efficiency of Pelton wheel is about:
A) 50–60%
B) 70–80%
C) 85–90%
D) 95–100%
Ans: C

Q46. A hydro plant with large storage is suitable for:
A) Peak load
B) Base load
C) Standby load
D) Both A and B
Ans: B

Q47. The runner of Kaplan turbine is:
A) Vertical shaft
B) Horizontal shaft
C) Both
D) None
Ans: C

Q48. Hydraulic turbines are classified on the basis of:
A) Head
B) Direction of flow
C) Operating principle
D) All of the above
Ans: D

Q49. The efficiency of hydro power plant decreases due to:
A) Silt in water
B) Cavitation
C) Poor maintenance
D) All of the above
Ans: D

Q50. Largest hydro power plant in India is:
A) Bhakra Nangal
B) Tehri Dam
C) Nathpa Jhakri
D) Sardar Sarovar
Ans: C