Question

If the heat of $110\,\,J$ is added to a gaseous system, whose internal energy is $40\,\,J$ , then the amount of external work done is:

• A. $180\,\,\text{J}$
• B. $70\,\,\text{J}$
• C. $110\,\,\text{J}$
• D. $30\,\,\text{J}$

Answer 1

Answer: (B)

$70\,\,\text{J}$

Answer 2

Heat added to the system $\Delta Q=110 \,J$
Internal energy $\Delta U=40\, J$
External work done is given by
$\Delta W=\Delta Q-\Delta U=110-40$
$= 70 \,J$