Heat transfer is an irreversible process if

Heat transfer is an irreversible process if

Options:

a. the temperature difference between the two bodies is infinitesimally small
b. the temperature difference between the two bodies is finite
c. both a. and b.
d. none of the above

Correct Answer: b. the temperature difference between the two bodies is finite

Explanation

If the temperature difference between the two bodies approaches zero, the heat transfer process approaches irreversibility. In a reversible heat transfer process the temperature difference is infinitely small. But to transfer a finite amount of heat through an infinitesimal temperature difference, we need infinite time or infinite area. But this is not possible. Actual heat transfer process takes place through an finite temperature difference and these are irreversible.