When heat is absorbed by the system and work is done by the system on the surroundings then
A) q is negative and w is positive.
B) both q and w are positive.
C) both q and w are negative.
D) q is positive and w is negative.
E) both q and w are zero.

Question

Quizplus · Accepted Answer

According to the first law of thermodynamics, ΔU = q + w, where ΔU is the change in internal energy of the system. As heat is absorbed by the system, q is positive. As work is done on the surroundings, the system loses energy and thus ΔU is negative. Therefore, w must be negative. Thus, q is positive and w is negative, leading to choice D.

When Heat Is Absorbed by the System and Work Is