When a process becomes irreversible due to heat interaction between system and surrounding at the boundary, irreversibility is

When a process becomes irreversible due to heat interaction between system and surrounding at the boundary due to finite temperature gradient, then the irreversibility is______

Options

a. internal irreversibility
b. external irreversibility
c. mechanical irreversibility
d. chemical irreversibility

Correct Answer: b. external irreversibility

Explanation

All the spontaneous processes are irreversible in nature. The irreversibility is caused by finite potential gradient like temperature gradient etc. or by any dissipative effect like friction. There are two types of irreversibility

i.) Internal irreversibility
ii.) External irreversibility

The external irreversibility occurs due to the temperature difference between the source and a working fluid at heat supply and the temperature difference between the sink and the working fluid at heat rejection. If the hypothetical heat source and sink is considered then the process becomes reversible.