Question

A battery is connected in series to a resistor, which is immersed in water (to prepare a nice hot cup of tea). Would you classify the flow of energy from the battery to the resistor as "heat" or "work"? What about the flow of energy from the resistor to the water?

Short answer

"Work" from the battery is applied to the resistor, and "heat" is applied to the water via the resistance.

Step-by-step solution

Step 1. Introduction.

When a current is passed through the heating element (Resistor), it becomes heated.

As a result, energy is flowing into the resistor, but it is due to electric current rather than a temperature differential, therefore the electric current is doing work on the resistor; there is no heat involved.

The temperature was then spread by the resistor due to the temperature difference between the resistor and the water.

This is depicted in the diagram.

Step 2. Diagram.