Question

A system undergoes a reversible adiabatic process. The entropy of the system :

• A. Remains constant
• B. May increase or may decrease
• C. Increases
• D. Decreases

Answer 1

The correct option is A Remains constant

In general, the temperature of the system may change during a process. If the process is reversible, the change in entropy is defined as
$S_f-S_i={\int }_i^f=\frac{△Q}{T}$
In an adiabatic reversible process, no heat is given to the system. Therefore, entropy of the system remains constant in such a process.