Reversibility

 All processes are divided into two types on the basis of second law of thermodynamics.

REVERSIBILITY

All processes are divided into two types on the basis of second law of thermodynamics.

1. Reversible process or ideal process

2. Irreversible process or actual process or natural process.

A process is performed in such a way that it should trace the same path when the process is reversed known as reversible process. It means that it does not follow the different path without producing any change in the universe when it is reversed. Also, both system and surroundings come to the initial states.

For example, consider a system initially at the state A. This system reaches state B at the end of successful completion of the process. The process taken from A to B is shown in Figure 2.8 by a path A - B. When the same process is reversed, it attains the initial state A by a same path as the process is already carried out. The work involved due to this process is known as reversible work or maximum work or ideal work. Any actual machine will always produce work less than this maximum work. If it produces more work, it will violate the second law of thermodynamics. To obtain a reversible process, it should infinitely be performed in a slow manner with an infinitesimal gradient to keep the every state in equilibrium state. So, a quasi- static process is a reversible process.