A carnot engine is a reversible heat engine operating between two temperatures,
The steps involved in a carnot cycle are explained as follows.
Step 1 :
Isothermal expansion of gas from state (P1, V1, T1) to state (P2, V2, T2) as shown in the figure.
Step 2 :
Adiabatic expansion of gas from (P2, V2, T1) to (P3, V3, T2)
Step 3 :
Isothermal compression of gas from (P3, V3, T2) to (P4, V4, T2)
Step 4 :
Adiabatic compression of gas from (P4, V4, T2) to (P1, V1, T1)
These steps constitute one carnot cycle.
The process is repeated thereafter.
The efficiency of carnot engine, \(\eta\) is given by
\(\eta = \frac{Q_1 - Q_2}{Q_1} = \frac{T_1 - T_2}{T_1}\)