Question

A gas is taken through the cycle $A \rightarrow B \rightarrow C \rightarrow A,$ as shown. What is the net work done by the gas?

• A. Zero
• B. -2000 J
• C. 2000 J
• D. 1000 J

Answer 1

Answer: (D)

1000 J

Answer 2

In a cyclic process, work done is equal to the area under the cycle and is positive if the cycle is clockwise and negative if the cycle is anticlockwise.

$\therefore$ The network done by the gas is
W = Area of the cycle ABCA
$\, \, \, \, =\frac {1}{2} \times (7-2) \times 10^{-3} \times (6-2) \times 10 ^5$
$\, \, \, \, =\frac {1}{2} \times (5) \times 10^{-3} \times 4 \times 10 ^5$
$\, \, \, \, =10 \times 10^2 J=1000 \, J$