Reversible process -
A Reversible process is that which can be retraced in opposite direction so that system and surrounding pass exactly through the same states as in the direct process .
If some work is done by the system in the direct process then same amount of work is done on the system in the reverse process . Similarly , if some heat is absorbed by the system from the surrounding in the direct process then same amount of heat energy is given back to the surrounding in the reverse process .
For a process to be reversible , it must satisfy the following conditions :
- The process must be a very slow so that the system is always in state of mechanical and thermal equilibrium . This system should be in chemical equilibrium .
- The system should be free from dissipative forces like friction , viscosity etc .
Irreversible process -
A process which is not reversible i.e which can not be treated in opposite direction by taking it exactly through same states as attained in the direct process . Such a process followed by reverse process always leaves some change in the system or surrounding .
Example - Conduction , diffusion etc
