250+ TOP MCQs on Carnotinization of Rankine Cycle and Answers

Power Plant Engineering Multiple Choice Questions on “Carnotinization of Rankine Cycle”.

1. In the T-S diagram of a Rankine cycle, the abscissa represents?
a) total entropy of turbine steam
b) partial entropy of turbine steam
c) partial enthalpy of turbine steam
d) none of the mentioned
Answer: a
Clarification: The T-S diagram of a Rankine Cycle has total entropy of turbine steam in the abscissa & temperature on the ordinate.

2. After the expansion of throttle steam, why is some steam extracted?
a) so that the total amount of steam in the entire system remains same
b) so that the variation in temperature is constant
c) so that pressure variation is constant
d) so that the total entropy is reduced
Answer: d
Clarification: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

3. The heat given up by the expansion of throttle steam is utilised in?
a) maintaining the heat flow in the system
b) reducing temperature variation in the system
c) heating the feedwater
d) cooling feedwater
Answer: c
Clarification: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

4. “Regenerative feedwater heating by turbine extraction” is often termed as?
a) Electrophoresis of Rankine cycle
b) Sterlinisation of Rankine cycle
c) Carnotization of Rankine cycle
d) None of the mentioned
Answer: c
Clarification: In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. That is why we often term regenerative feedwater heating by turbine extraction as carnotization of rankine cycle.

5. A regenerative feedwater heating cycle with an infinite number of feedwater heaters has efficiency equal to?
a) Brayton cycle
b) Carnot cycle
c) Diesel cycle
d) Otto cycle
Answer: b
Clarification: In the T-S diagram, the area of the parallelogram representing the cycle output will be equal to the area of the rectangle representing the output of the Carnot cycle. Thus, the efficiency of a regenerative feedwater heating cycle with an infinite number of feedwater heaters is equal to that of a carnot cycle.

6. In the T-S diagram, the process of heating from condenser to boiler saturation temperature when the number of turbine extraction stages are finite is?
a) Reversible
b) Irreversible
c) Adiabatic
d) None of the mentioned
Answer: b
Clarification: When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

7. For the process of heating from condenser to boiler saturation temperature to be reversible, the number of extraction stages involved in the entire cycle should be?
a) Zero
b) One
c) Infinite
d) Finite
Answer: c
Clarification: When the number of extraction stages are finite, the process is irreversible. On the contrary, when there are infinite extraction stages, the process becomes reversible.

8. Which of the processes immediately follows the expansion of throttle steam?
a) heat given up by the steam is added to feedwater
b) heating from condenser to boiler saturation temperature
c) carnotization of rankine cycle
d) none of the mentioned
Answer: a
Clarification: The expansion of throttle steam is mainly to reduce the total entropy & the heat given up by this steam is added to feed water, thereby heating it.

9. The output from boiler goes to?
a) Turbine
b) Condenser
c) Pump
d) Economiser
Answer: a
Clarification: The sequence of flow is
Boiler, Turbine, Condenser, Pump, Economiser.

10. The area of parallelogram in the T-S diagram representing the cycle output is equal to?
a) area of rectangle representing the output of the Carnot cycle
b) area of the triangle representing the output of the Carnot cycle
c) area of the square representing the output of the Carnot cycle
d) none of the mentioned
Answer: a
Clarification: From the T-S diagram the area of parallelogram representing the cycle output is equal to the area of rectangle representing the output of the Carnot cycle.