25 J of heat is supplied to a system and work done by the system

25-j-of-heat-is-supplied-to-a-system-and-work-done-by-the-system

25 J of heat is supplied to a system and work done by the system is 10 J. What is the change in internal energy of the system?

A. 10 J

B. 15 J

C. 25 J

D. 35 J

I have been asked this question during an interview.

This intriguing question originated from Energy balance for Different type of systems topic in chapter Miscellaneous of Chemical Process Calculation

The correct option is B. 15 J

To explain I would say: For the given process ∆U = -W +Q.