Power Plant: Objective Questions


21. Which one of the following is used to bring down the speed of an impulse steam turbine to practical limits?

A. A gearbox

B. A large flywheel

C. Compounding of the turbine

D. A centrifugal governor

Click for Answer/Explanation

Correct Answer is C

22. An impulsive turbine produces 50 kW of power when the blade’s mean speed is 400 m/s. The rate of change of momentum tangential to the rotor-

A. 125 N

B. 150 N

C. 175 N

D. 200 N

Click for Answer/Explanation

Correct Answer is A

Power = F × V

Put the values and find the value of F

23. When are shock waves formed in air compressor-

A. Mach Number < 0.9

B. Mach Number > 0.9

C. Mach Number = 2

D. Mach Number changes suddenly from one value to another

Click for Answer/Explanation

Correct Answer is C

Shock occurs when the flow condition is supersonic and after the shock it becomes sub-sonic.

24. In which one of the following steam turbines, steam is taken from various points along the turbine, solely for feed-water heating-

A. Bleeder turbine

B. Extraction turbine

C. Reheat turbine

D. Regenerative turbine

Click for Answer/Explanation

Correct Answer is D

25. With natural Uranium which of these is used as a moderator?

A. Heavy water

B. Beryllium

C. Graphite

D. All of these

Click for Answer/Explanation

Correct Answer is D

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