During the course of a demonstration the professor is called away. When he returns he finds a beaker of water that was at room temperature is now at a slightly higher temperature. There is a stirring rod on the desk and a cigarette lighter. The professor can assume that the temperature increase is due to
A) heat added to the system.
B) mechanical work done on the system.
C) either heat added or mechanical work done.

Question

Quizplus · Accepted Answer

The temperature increase in the water could be due to heat added directly through the use of the cigarette lighter or through mechanical work done on the system by stirring the water with the stirring rod. Both processes can increase the temperature of the water.

During the Course of a Demonstration the Professor Is Called