Question

A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5J and 8J, respectively. Now gas is brought back at A by another process during which 3J of heat is evolved. In this reverse process of B to A:

• A. 10 J of the work will be done by the gas.
• B. 6 J of the work will be done by the gas.
• C. 10 J of the work will be done by the surrounding on gas.
• D. 6 J of the work will be done by the surrounding on gas

Answer 1

The correct option is D 6 J of the work will be done by the surrounding on gas

$\Delta U_{AB}=q+w=+5+(-8)=-3$

$q=-3,\Delta U_{BA}=+3$

$\Delta U_{BA}=q+w$

$\Rightarrow 3=-3+w\Rightarrow w=+6$

$\Delta U_{BC}=-5kJmo{l}^{-1},q_{AB}=2kJmo{l}^{-1}$

$W_{AB}=-5kJmo{l}^{-1},W_{CA}=3kJmo{l}^{-1}$ (work done on the system).