250+ TOP MCQs on Rankine Cycle and Carnot Cycle and Answers

Power Plant Engineering Multiple Choice Questions on “Rankine Cycle and Carnot Cycle”.

1. Ideal ‘Rankine Cycle’ is a __________ process.
a) Reversible
b) Irreversible
c) Reversible & Irreversible
d) None of the mentioned

Answer: a
Clarification: Ideal Rankine Cycle is a reversible process.

2. For analytical purposes, the Rankine Cycle is assumed to be in _____________
a) Unsteady flow operation
b) Turbulent flow operation
c) Steady flow operation
d) Laminar flow operation

Answer: c
Clarification: For analytical purposes, always steady flow operation is considered, as in unsteady flow, the various fluid properties vary considerably which remain same when the steady flow operation is assumed.

3. The net work done in a Rankine Cycle is the difference of _____________
a) Condenser work & Boiler work
b) Boiler work & Pump work
c) Turbine Work & Pump work
d) Condenser work & Pump work

Answer: c
Clarification: The net work done in a Rankine Cycle is given by,
W_net = W_t – W_p.

4. In a Rankine Cycle, heat input is provided to ___________
a) Condenser
b) Pump
c) Turbine
d) Boiler

Answer: d
Clarification: As the heating of the liquid working fluid occurs in the Boiler, the heat input is provided to the Boiler for the same.

5. In a Rankine Cycle, heat output is obtained from ___________
a) Condenser
b) Boiler
c) Turbine
d) Pump

Answer: a
Clarification: As the heated water comes to the condenser, it loses its heat & gets condensed. The heat output is obtained from Condenser.

6. The water that flows from the Pump is?
a) Compressible
b) Incompressible
c) Unsteady
d) None of the mentioned

Answer: b
Clarification: The water flowing through the pump is incompressible so as to extract work from the turbine.

7. Steam Rate is the reciprocal of _________
a) Net work done
b) Heat extracted from condenser
c) Heat given to reciprocal
d) Work done by turbine

Answer: a
Clarification: Steam Rate is given by,
Steam Rate = 1/W_net.

8. Which of these is sometimes neglected?
a) Turbine work
b) Pump work
c) Condenser heat
d) Boiler heat

Answer: b
Clarification: Pump Work is very small as compared to Turbine Work & so is often neglected.

9. Efficiency of a Rankine Cycle is also expressed as __________
a) Capacity Ratio
b) Heat Rate
c) Heat Ratio
d) Steam Rate

Answer: b
Clarification: The relation between Heat Rate & Efficiency is,
Heat Rate = Efficiency of a Rankine Cycle.

10. Steam Power Plants are more popular in electric power generation because ___________
a) Work output of turbine is very large than work input to the pump
b) Work output of turbine is very small than work input to the pump
c) Work output of turbine is equal to work input to the pump
d) None of the mentioned

Answer: a
Clarification: In a Steam Power Plant, the positive difference of turbine work & pump work makes it useful in electricity generation.

11. Which is the most common type of Evaporator?
a) Flooded Evaporator
b) Plate Evaporator
c) Coil Evaporator
d) Brine Evaporator

Answer: b
Clarification: The most common type is a coil winding on a plate & so the name ‘plate evaporator’.

12. In Rankine Cycle, water is converted to saturated liquid in ___________
a) Evaporator
b) Economizer
c) Superheater
d) Preheater

Answer: b
Clarification: The saturation of water occurs in an Economizer in a Rankine Cycle.

13. If Evaporator & Condenser pressures are p & q, the intercooler pressure P is given as?
a) P = pq
b) P = p/q
c) P = (pq)^(1/2)
d) P = p²q

Answer: c
Clarification: The relation between Intercooler pressure, Evaporator & Condenser is,
P = (pq)^(1/2).

14. Phase change at constant pressure takes place in _____________
a) Economiser
b) Evaporator
c) Superheater
d) Air-Preheater

Answer: c
Clarification: Superheater undergoes a change in phase at constant pressure.

15. Which of these factors don’t cause Internal Irreversibility of a Rankine cycle?
a) Throttling
b) Mixing
c) Fluid Friction
d) Fluid flow

Answer: d
Clarification: The Rankine cycle is an Irreversible cycle. For a cycle to be irreversible naturally throttling, mixing & friction in fluids are the factors that cause this Irreversibility.