A thermodynamic system is taken from an original state to an intermediate state by the linear process shown in the figure. Its volume is then reduced to the original value from $E$ to $F$ by an isobaric process. Calculate the total work done by the gas from $D$ to $E$ to $F$.

1. $450J$
2. $900J$
3. $600J$
4. $225J$

The correct option is A $450J$

Total work done by the gas from $D$ to $E$ to $F$ = Area of $△DEF$

Area of $△DEF=\left(1/2\right)DE\times EF$

Where,

$DF$ = Change in pressure

$=600N/m^2-300N/m^2$

$=300N/m^2$

$FE$ = Change in volume

$=5.0m^3-2.0m^3$

$=3.0m^3$

Area of $△DEF=\left(1/2\right)\times 300\times 3=450J$

Therefore, the total work done by the gas from $D$ to $E$ to $F$ is $450J$.