The irreversibility of a process occurs due to.

The irreversibility of a process occurs due to

a. lack of equilibrium during the process
b. involvement of dissipative effects
c. either a. or b. or both
d. none of the above

Correct Answer : c. either a. or b. or both

Explanation :

A reversible process is carried out infinitely slowly, so that every state passed through by the system is an equilibrium state. In the irreversible process every state will not be an equilibrium state as it is carried out very fast. Only the first and the last state of the irreversible process are the equilibrium states. Therefore lack of equilibrium is a cause of irreversibility.
In a dissipative effect the energy is transformed from one form to another form and the final form of energy has a less capacity to do mechanical work. Thus this process becomes irreversible. Therefore involvement of dissipative effect is an another cause of irreversibility.