Question

During an adiabatic process an object does $100J$ of work and its temperature decreases by $5K$. During another process it does $25J$ of work and its temperature decreases by $5K$. Its heat capacity for $2^{nd}$ process is

• A. $20J/K$
• B. $24J/K$
• C. $15J/K$
• D. $100J/K$

Answer 1

Answer: (C)

$15J/K$

For adiabatic process, $dU=-100J$
which remains same for other processes also.
Let C be the heat capacity of 2nd process then
$-\left(C\right)5=dU+dW$
$=-100+25=-75$
$\therefore C=15J/K$