Question

A carnot cycle is having maximum efficiency because

• A. it comprises of two adiabatic process which requires no heat in its execution.
• B. it comprises of two isothermal process.
• C. its every process is reversible
• D. none of the above

Answer 1

Answer: (C)

its every process is reversible

Carnot cycle consists of 4 process. All of them are ideal and practically not possible.

1.Isothermal heat addition- Nothing can be more efficient than this heating since no finite temperature difference exists between heat source and receiver. Hence it is a reversible process and most efficient,

2.Isentropic(reversible adiabatic) expansion- Most efficient expansion, as no heat loss is taking place, full energy is utilised only for expansion and thereby doing work.

3.Isothermal heat rejection- Most efficient heat rejection to a heat sink at same temperature.

4.Isentropic compression- Compressed(without friction) with no heat lost to surrounding. Power input is used only for increasing the pressure and temperature.

In this cycle every process is reversible and hence it is most efficent.

When the cycle is completed input energy and power is used only for the purpose it was intended. Output was completely used for intended purpose