A system is acted on by its surroundings in such a way that it receives 70 J of heat while simultaneously doing 40 J of work.What is its net change in internal energy?

A) 110 J
B) 30 J
C) zero
D) −30 J
E) −110 J

Question

A system is acted on by its surroundings in such a way that it receives 70 J of heat while simultaneously doing 40 J of work.What is its net change in internal energy?
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A) 110 J
B) 30 J
C) zero
D) −30 J
E) −110 J

Quizplus · Accepted Answer

The net change in internal energy (ΔU) can be calculated using the first law of thermodynamics: ΔU = Q - W, where Q is the heat added to the system and W is the work done by the system. Here, ΔU = 70 J - 40 J = 30 J.

A System Is Acted on by Its Surroundings in Such