Heating Effect of Electric Current

Why do wires get hot?

When electric current flows through a conductor, the material resists the flow of electrons. This opposition is called Resistance.

• To overcome this resistance, the battery does work.
• This work is converted into Heat Energy.

This is known as the Heating Effect of Electric Current.

The Nichrome Wire Experiment

If you pass current through a Nichrome wire, it gets red hot very quickly. If you do the same with a Copper wire, it barely gets warm.

• Reason: Nichrome has very high resistance compared to copper.
• Rule: Higher Resistance = More Heat.

Factors Affecting Heat Generation

The amount of heat produced depends on:

1. Material: (Nichrome heats more than Copper).
2. Length: Longer wires offer more resistance $\rightarrow$ More heat.
3. Thickness: Thinner wires offer more resistance $\rightarrow$ More heat.
4. Current Magnitude: More current $\rightarrow$ More heat.
5. Duration: Longer time $\rightarrow$ More heat.

Applications

We use specific coils called Heating Elements in appliances.