Given that,
Work done by the system = 125 J
Energy released when it cools down = 438 J
To find,
The change in internal energy.
Solution,
As heat is released by the system, Q = -438 J
Work done by the system, W = -125 J
Using the first law of thermodynamics. The change in internal energy is given by :
[tex]\Delta U=Q-W\\\\=-438-125\\\\=-563\ J[/tex]
So, the change in internal energy is 563 J.
