Question

Heat given to a system is 35 J and work done by the system is 15 J. The change in the internal energy of the system will be:

• A. 50 J
• B. 20 J
• C. 30 J
• D. 40 J

Answer 1

The correct option is B 20 J

According to the first law of thermodynamics,
$△U=Q+W$
$=35-15=20J$