Question

An ideal gas is taken in a cyclic process as shown in the figure. Calculate

1. work done by the gas
2. work done on the gas
3. Net work done in the process

Answer 1

a. Work done by the gas (along with AB)

W = P × ΔV = 600 × 3 = 1800 J

W = 1.8 kJ

b. Work is done on the gas (along with BC)

W = −P × ΔV = −400 × 3 = −1200 J

W = −1.2 kJ

c. Net work done in the process = Area under the curve AB

= Rectangle area + triangle area

= `("l" xx "b") + (1/2 xx "b" xx "h")`

= `(400 xx 3) + (1/2 xx 3 xx 200)`

= 1200 + 300

= 1500 J

W = 1.5 kJ