# Power Plant Questions and Answers – Steam Turbines Basics – II

This set of Power Plant Questions and Answers for Entrance exams focuses on “Steam Turbines Basics – II”.

1. The ratio of the work done on the blades to the energy supplied to the blades is called ____________
a) gross or stage efficiency
c) nozzle efficiency
d) mechanical efficiency

Explanation: Blading Efficiency is the ratio of work done on the blades to the energy supplied to the blades of a turbine.

2. A nozzle is said to be a convergent nozzle when?
a) the cross-section of the nozzle increases continuously from entrance to exit
b) the cross-section of the nozzle decreases continuously from entrance to exit
c) the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
d) none of the mentioned

Explanation: In case of a convergent nozzle, the cross-section of the nozzle decreases continuously from entrance to exit.

3. Multi-stage steam turbines are of the ___________
a) reaction type
b) velocity compounded type
c) pressure compounded type
d) all of the mentioned

Explanation: There are various types of multi-stage steam turbines which are, reaction; velocity compounded; & pressure compounded, respectively.

4. The impulse reaction turbine has its driving force ___________
a) partly as an impulsive force and partly as a reaction force
b) as an impulsive force
c) as a reaction force
d) none of the mentioned

Explanation: The impulse reaction turbine has its driving force partly as an impulsive force & partly as a reaction force as the components add to the resultant.

5. In a nozzle, whole frictional loss is assumed to occur between ___________
a) inlet and throat
b) throat and exit
c) inlet and outlet
d) none of the mentioned

Explanation: In a nozzle, whole frictional loss is assumed to occur between the throat & exit of the nozzle.
Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

6. The ratio of total useful heat drop to the total isentropic heat drop is called?
a) Rankine efficiency
b) Stage efficiency
c) Internal efficiency
d) None of the mentioned

Explanation: The ratio of total useful heat drop to the total isentropic heat drop is called internal efficiency.

7. What is the action of steam in a steam turbine?
a) neither static nor dynamic
b) dynamic
c) static
d) both dynamic & static

Explanation: Steam action in a steam turbine is Dynamic.

8. The critical pressure gives the velocity of steam at the throat ___________
a) equal to the velocity of sound
b) more than velocity of sound
c) less than the velocity of light
d) none of the mentioned

Explanation: The critical pressure gives the velocity of steam at the throat which is equal to the velocity of sound.

9. The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be ___________
a) 0.67
b) 0.4
c) 0.5
d) 0.56

Explanation: The required degree of reaction will be 0.67.

10. The flow through a nozzle is regarded as ___________
a) isothermal flow
b) isobaric flow
c) isochoric flow
d) isentropic flow

Explanation: The flow through a nozzle is regarded as isentropic flow.

Sanfoundry Global Education & Learning Series – Power Plant Engineering.

To practice all areas of Power Plant for Entrance exams, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]