Question
A thermodynamic system is taken from an original state to an intermediate state by the linear process shown in Fig. (12.13).

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.
Solution
Total work done by the gas from D to E to F = Area of ΔDEF
Area of ΔDEF =
DE × EF
where,
DF = Change in pressure
= 600 N/m2 – 300 N/m2
= 300 N/m2
FE = Change in volume
= 5.0 m3 – 2.0 m3
= 3.0 m3
Area of ΔDEF = (1/2) × 300 × 3
= 450 J
Therefore, the total work done by the gas from D to E to F is 450 J.
Area of ΔDEF =

where,
DF = Change in pressure
= 600 N/m2 – 300 N/m2
= 300 N/m2
FE = Change in volume
= 5.0 m3 – 2.0 m3
= 3.0 m3
Area of ΔDEF = (1/2) × 300 × 3
= 450 J
Therefore, the total work done by the gas from D to E to F is 450 J.