Question

The $P-V$ diagram of a diatomic ideal gas system going under cyclic process as shown in figure. The work done during an adiabatic process $CD$ is $(\text{use}\gamma =1.4):$

• A. $–400\text{J}$
• B. $–500\text{J}$
• C. $200\text{J}$
• D. $400\text{J}$

Answer 1

The correct option is B $–500\text{J}$

work done during adiabatic process is given by, $W_{CD}=\frac{nR\Delta T}{1-\gamma }=\frac{P_f{V}_f-P_i{V}_i}{1-\gamma }$

Substituting the data given the question we get,

$W_{CD}=\frac{200\times 3-4\times 100}{1-1.4}$

$W_{CD}=\frac{600-400}{-0.4}=-\frac{2000}{4}=-500\text{J}$

Hence, option (b) is the correct answer.