question_answer

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

A) \[10\text{ }J\] of the work will be done by the gas.

B) \[6\text{ }J\] of the work will be done by the gas.

C) \[10\text{ }J\] of the work will be done by the surrounding on gas.

D) \[6\text{ }J\] of the work will be done by the surrounding on gas.

Correct Answer: D

Solution :

[d] \[\Delta {{U}_{AB}}=q+w=+5+(-8)=-3\] \[q=-3,\Delta {{U}_{BA}}=+3\] \[\Delta {{U}_{BA}}=q+w\] \[\Rightarrow 3=-3+w\Rightarrow w=+6J\] (work done on the system).