250+ TOP MCQs on Effect of Pressure and Temperature and Answers

Steam and Gas Turbines Multiple Choice Questions on “Effect of Pressure and Temperature”.

1. When boiler pressure is increased efficiency is ____________
a) decreased
b) increased
c) remains constant
d) none of the mentioned

Answer: b
Clarification: When boiler pressure is increased efficiency is increased.

2. Why is operating pressure of boiler designed?
a) To maintain economic equivalence
b) For not decreasing efficiency
c) No such operating pressures are designed
d) None of the mentioned

Answer: a
Clarification: If boiler pressure is increased efficiency also increases. But if we keep on increasing boiler pressure to increase efficiency, Boilers that work under high pressure as costly and so boiler operating pressures are designed so that for a particular boiler it does not work beyond that pressure and it maintains economical equivalence.

3. When boiler pressure is increased __________
a) efficiency is increased
b) Qh is increased
c) efficiency & Qh is increased
d) none of the mentioned

Answer: c
Clarification: When boiler pressure is increased Qh increases as a result efficiency is increased.

4. Can we keep on increasing the pressure of the boiler to increase its efficiency?
a) Yes
b) No

Answer: b
Clarification: Boilers that work under high pressure are much more costly.

5. What happens to the efficiency when temperature is increased in rankine cycle?
a) Increased
b) Decreased
c) Remains constant
d) None of the mentioned

Answer: a
Clarification: When the temperature is increased reheating capacity of the steam increases and thus efficiency also increases.

6. Increase in temperature increases __________
a) reheating capacity of the fluid
b) thermal efficiency
c) reheating capacity of the fluid & thermal efficiency
d) none of the mentioned

Answer: c
Clarification: When reheating capacity is increased it automatically increases the thermal efficiency.

7. When condenser pressure is lowered efficiency _________
a) increases
b) decreases
c) does not effect
d) none of the mentioned

Answer: a
Clarification: When operating pressure of condenser is lowered, Heat rejecting temperature also lowers which eventually increases the efficiency.

8. Superheating the steam increases efficiency.
a) True
b) False

Answer: a
Clarification: Average Temperature of steam can be increased without increasing the pressure by superheating.

9. Superheating the steam results in __________
a) increasing the efficiency
b) decreases the moisture content
c) increasing efficiency & decreases the moisture content
d) none of the mentioned

Answer: c
Clarification: Superheating the steam increases the steam temperature and also decreases the moisture content in the steam.

10. When boiler pressure is increased __________
a) temperature also increased
b) efficiency also increases
c) temperature & efficiency increases
d) none of the mentioned

Answer: a
Clarification: When boiler pressure is increased steam temperature increases which increases efficiency.