250+ TOP MCQs on Actual Vapor Cycle Processes and Comparison of Rankine and Carnot Cycles and Answers

tough Thermodynamics questions and answers on “Actual Vapor Cycle Processes and Comparison of Rankine and Carnot Cycles”.

1. The thermal efficiency of the cycle is
a) Q2 / Wnet
b) Wnet / Q2
c) Wnet / Q1
d) Q1 / Wnet
Answer: c
Clarification: These work and heat quantities are the measured values for actual cycle.

2. Which of the following losses occur in a cycle?
a) piping losses
b) pump losses
c) turbine losses
d) all of the mentioned
Answer: d
Clarification: These are the major losses that happen in a cycle including condenser losses.

3. The important piping losses include
a) pressure drop due to friction
b) heat loss to surroundings
c) both of the mentioned
d) none of the mentioned
Answer: c
Clarification: These two factors contribute to the piping losses.

4. The heat transfer and the pressure drop reduces the availability of steam.
a) true
b) false
Answer: a
Clarification: These two factors reduces the steam availability entering the turbine.

5. The losses in boiler include
a) pressure drop from pump to boiler
b) pressure drop in boiler
c) both of the mentioned
d) none of the mentioned
Answer: c
Clarification: Due to this, water entering the boiler is pumped at a very high pressure hence requiring additional pump work.

6. The main losses in turbine include
a) heat loss to surroundings
b) friction losses
c) both of the mentioned
d) none of the mentioned
Answer: c
Clarification: These are the two major losses in turbine.

7. Heat loss from turbine is generally neglected.
a) true
b) false
Answer: a
Clarification: This is true except for small turbines where we have to consider turbine losses.

8. The losses in pump is due to
a) heat loss to surroundings
b) irreversibilities associated with fluid friction
c) both of the mentioned
d) none of the mentioned
Answer: b
Clarification: The losses in pump are similar to those of turbine.

9. The losses in condenser are ____
a) small
b) large
c) always constant
d) none of the mentioned
Answer: a
Clarification: Hence condenser losses are mostly neglected.

10. The condenser losses include
a) loss of pressure
b) cooling of condensate below saturation temperature
c) both of the mentioned
d) none of the mentioned
Answer: c
Clarification: These are main losses in condenser which are very small.

11. The efficiency of Carnot cycle is ____ the efficiency of Rankine cycle.
a) less than
b) greater than
c) equal to
d) none of the mentioned
Answer: b
Clarification: The Carnot cycle has the maximum possible efficiency.

12. The only process which is different in Carnot and Rankine cycle is
a) compression in pump
b) expansion in turbine
c) heat rejection process
d) heat addition process
Answer: d
Clarification: In Rankine cycle, the heat addition process is reversible and at constant pressure and in Carnot cycle it is reversible and isothermal.

13. The Carnot cycle cannot be realized in practice.
a) true
b) false
Answer: a
Clarification: The reason being that the pump work is very large.