PV^y = constant, holds good for an isentropic process, which is

A. Reversible and isothermal

B. Isothermal and irreversible

C. Reversible and adiabatic

D. Adiabatic and irreversible

Answer: Option C

Solution(By Examveda Team)

We know from second law of thermodynamics for an reversible process $$Tds = \delta Q$$
So, $$dS =0$$
When the process is adiabatic.
Hence for a reversible adiabatic process the entropy is constant.