$\Delta W=20 \mathrm{KJ}$
$\Delta Q=16 \mathrm{KJ}$
$\therefore \Delta U=\Delta Q-\Delta W=-4 K J$
since, $U$ is a state function. Therefore, value of $DU$ in both expansions remain same.
Thus, for second expansion $:-$
$\Delta U=-4 K J, \Delta Q=9 K J$
$\therefore$ By first law of the thermodynamics
$\Delta \mathrm{W}=\Delta \mathrm{Q}-\Delta \mathrm{U}=13 \mathrm{KJ}$

(image)
$(A)$ Process $I$ is an isochoric process $(B)$ In process $II$, gas absorbs heat
$(C)$ In process $IV$, gas releases heat $(D)$ Processes $I$ and $III$ are $not$ isobaric

Step $1$ It is first compressed adiabatically from volume $V_{1}$ to $1 \;m ^{3}$.
Step $2$ Then expanded isothermally to volume $10 \;m ^{3}$.
Step $3$ Then expanded adiabatically to volume $V _{3}$.
Step $4$ Then compressed isothermally to volume $V_{1}$. If the efficiency of the above cycle is $3 / 4$, then $V_{1}$ is ............ $m^3$