An ideal gas is taken through the cycle A→B→C→A as shown in figure. If net heat supplied to the gas in the cycle is 5J, the work done by the gas in the process C→A is
q = +5J
W = WAB + WBC +WAC
= -10(2-1) + 0 + WAC
( WBC = 0 since it is at constant volume)
5 = -10+WAC
WAC = +5+10 = +15J