Which of the processes described below are irreversible? The increase in temprature of an iron rod by hammering it.

Question

Which of the processes described below are irreversible? 

(a) The increase in temprature of an iron rod by hammering it. 

(b) A gas in a small cantainer at a temprature T₁ is brought in contact with a big reservoir at a higher temprature T₂ which increases the temprature of the gas.

(c) A quasi-static isothermal expansion of an ideal gas in cylinder fitted with a frictionless piston.

(d) An ideal gas is enclosed in a piston cylinder arrangement with adiabatic walls. A weight W is added to the piston, resulting in compression of gas.

Answer 1

(a) The increase in temprature of an iron rod by hammering it. 

(b) A gas in a small cantainer at a temprature T₁ is brought in contact with a big reservoir at a higher temprature T₂ which increases the temprature of the gas.

(d) An ideal gas is enclosed in a piston cylinder arrangement with adiabatic walls. A weight W is added to the piston, resulting in compression of gas.