Question

A system absorbs 52 joules of heat and does work using 25 joules of energy. What is the change in the internal energy of the system?

Answer 1

B. 27 joules is correct

Answer 2

The change in internal energy is
`\Delta U=Q+W`. Where
`\Delta U` is change in internal energy.
`Q` is heat added to the system (absorbed by the system).
`W` work done on the system.
`W` is taken as positive if work is done on the system and negative if work is done by the system. Here
`Q=52` and
`W=-25`, hence change in internal energy is

`image`

Change in internal energy of the system is 27 J. Internal energy increases.