Question

What is the expression for Joule's law of heating?

Answer 1

When a current flows through a conductor, heat energy generates in the conductor.

The heating effect of electric current depends on three factors.

1. The resistance of the conductor: A higher resistance produces more heat.
2. The time for which the current flows: Longer the time, the amount of heat production is high.
3. Amount of current: Higher the current, the amount of heat generation is also large.
4. Hence the heating effect produced by an electric current ($I$) through a conductor of$resis\tan ceRforatimeT$is given by $H=I^{2}Rt$. This equation represents Joule's law of heating.
5. From the above equation, the heat energy is proportional to the square of the current produced in the conductor.

Hence, $H=I^{2}Rt$ is the expression for Joule's law of heating.