Question

A system is taken from state $A$ to state $B$ along two different paths $1$ and $2$. The heat absorbed and work done by the system along these two paths are $Q_{1}$ and $Q_{2}$, and $W_{1}$ and $W_{2}$ respectively. Then

• A. $Q_{1}=Q_{2}$
• B. $W_{1}=W_{2}$
• C. $Q_{1}-W_{1}=Q_{2}-W_{2}$
• D. $Q_{1}+W_{1}=Q_{2}+W_{2}$

Answer 1

Answer: (C)

A system is taken from state A to state B along 2 different paths 1 and 2 . The heat absorbed and work done by the system along these 2 paths are $Q_{1}, Q_{2}$ and $W _{1}, W _{2}$
By first law of thermodynamics
$
Q _{1}+\left(- W _{1}\right)= Q _{2}+\left(- W _{2}\right)
$
Hence $Q _{1}- W _{1}= Q _{2}- W _{2}$ is correct.