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)

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 $
$= 70 \,J$