If 900 Joules of heat is added to a system, and the internal energy increases by 800 Joules, how much work is done by the system?
A) -1700 J
B) -100 J
C) 900 J
D) 100 J
E) 1700 J

Question

Quizplus · Accepted Answer

According to the first law of thermodynamics, the change in internal energy (ΔU) is equal to the heat added to the system (Q) minus the work done by the system (W): ΔU = Q - W. Here, ΔU = 800 J and Q = 900 J. Solving for W gives W = Q - ΔU = 900 J - 800 J = 100 J.

If 900 Joules of Heat Is Added to a System