Which of the process described below are irrevesible?

Options

A. The increase in temperatre of an iron rod by hammering it
B. gas in a small container at a temperature `T_(1)` is brough in contanct with a big reservoir at a higher temperature `T_(2)` which increase the temperature of the gas
C. A quasi-static isothermal expansion of a n ideal gas in cylinder fitted with a frictionless piston
D. An ideal gas is enclosed in apiston cylinder arrangement with adiabatic walls. A weight w is added to the piston, resulting in compression of gas.

Answer

A, B, D

Explanation

(a) When the rod is hammered, the external work is done on the rod which increases its temperature. The process cannot be retracted itself
(b) In this process energy in the form of heat is transferred to the gas in the small container by big reservoir at temperature `T_(2)`.
(d) As the widht is added to the cylinder arangement in the form of external pressure hence, it cannot be reversed back itself.