Question

If the heat of $110\text{J}$ is added to a gaseous system and it acquires internal energy of $40\text{J}$, then the amount of internal work done is

• A. $40\text{J}$
• B. $70\text{J}$
• C. $150\text{J}$
• D. $110\text{J}$

Answer 1

The correct option is B $70\text{J}$

Here, $Q=110\text{J},dU=40\text{J},W=?$
From 1st law, $Q=dU+W$
$\Rightarrow W=Q-dU=110-40=70\text{J}$