Question

$A$ gas can be taken from $A$ to $B$ via two different processes $ACB$ and $ADB$.

When path $ACB$ is used $60J$ of heat flows into the system and $30J$ of work is done by the system. If path $ADB$ is used work done by the system is $10J$. The heat (in joule) flow into the system in path $ADB$ is :

Answer 1

Answer: 40

$\Delta U$ remains same for both paths $ACB$ and $ADB$
$\Delta Q_{ACB}=\Delta W_{ACB}+\Delta U_{ACB}$
$\Rightarrow 60J=30J+\Delta U_{ACB}$
$\Rightarrow U_{ACB}=30J$
$\therefore \Delta U_{ADB}=\Delta U_{ACB}=30J$
$\Delta Q_{ADB}=\Delta U_{ADB}+\Delta W_{ADB}$
$=10J+30J=40J$