Question

A thermodynamic system undergoes a cyclic process ABC as shown in the diagram. The work done by the system per cycle is

• A. -750 J
• B. 750 J
• C. 1250 J
• D. - 1250 J

Answer 1

Answer: (A)

-750 J

Answer 2

Work done =$p\times\Delta v$
Work done = Area of triangle ABC
$\therefore\, W=\frac{1}{2}\left(10-5\right)\times\left(100-400\right)=\frac{5}{2}\times\left(-300\right)=-750 J$
The negative sign means the work is done by the system.