Question

Consider the cyclic process ABCA, shown in figure, performed on a sample of 2.0 mol of an ideal gas. A total of 1200 J of heat is withdrawn from the sample in the process. Find the work done by the gas during the part BC.

Answer 1

n = 2 mole

$\Delta \text{Q}=-1200\text{J}$

$\Delta \text{U}=0$ (During cyclic process)

$\Delta \text{Q}=\Delta \text{U}+\Delta \text{W}$

$\Rightarrow -1200={\text{W}}_{\text{AB}}+{\text{W}}_{\text{BC}}+{\text{W}}_{\text{CA}}$

$\Rightarrow -1200=\text{nR}\Delta \text{T}+{\text{W}}_{\text{BC}}+0$

$\Rightarrow -1200=2\times 8.3\times 200+{\text{W}}_{\text{BC}}$

${\text{W}}_{\text{BC}}=-400\times 8.3-1200$

$=-4520\text{J}$