Question

Between two isotherms at temperatures $2T$ and $T$, a process $ABCD$ is performed with an ideal monatomic gas. $AB$ and $CD$ are adiabatic expansion processes and $BC$ is isobaric expansion process. The average molar specific heat capacity of the overall process with be

• A. $-\frac{3R}{2}$
• B. $\frac{5R}{2}$
• C. $\frac{3R}{2}$
• D. $-\frac{5R}{2}$

Answer 1

The correct option is D $-\frac{5R}{2}$

$△Q_{net}=△Q_{AB}+△Q_{BC}+△Q_{CD}=0+n{C}_p(T_C-T_B)+0$

$C=\frac{1}{n}\frac{△Q_{net}}{(T_D-T_A)}=-\frac{5R}{2}$

$\therefore \left(d\right)$