Question

During an adiabatic expansion of $5moles$ of gas, the internal energy decreases by $75J$. The work done during the process is

• A. $-75J$
• B. $0J$
• C. $15J$
• D. $75J$

Answer 1

The correct option is D $75J$

Change in internal energy is given as $dU=-75J$

Using first law, we have $dQ-dW=dU$.

For adiabatic process we have $dQ=0$,

$\therefore$ $0-dW=dU$

Thus we get $dW=-dU=75J$