Application of Heating Effect of Electrical Current

We have all used a water-heater or an iron box at least once

Both of them have a common thing in them, that is they can generate heat

They produce heat, only when electric current is passing through them

And James Prescott Joule was the first person who saw this effect of generation of heat when current is passing through a substance

So, what happens is whenever electric current or electric charges try to flow through a substance

That substance will oppose the flow of charges as they have resistance

By doing so, the resistors will consume the electrical energy the charges have and convert it into another form like heat and light

Joule observed this and gave a law to explain this production of heat due to current which is now known as Joule's law of heating

It is given by the formula

where, Q = Heat Energy released, I = Electric current in the wire, R = Resistance of the wire, t = time for which the circuit is on

So we can say that more heat is generated when the current and the resistance are high. It is also dependent on the time for which the circuit was on

The Heating effect of electric current has many practical applications

One such application is a light bulb

One such application is a light bulb (that is the production of light)

Bulbs have a filament(coil-like structure) inside them and current passes through this element

This filament is made of tungsten which has a very high resistance

So, as soon as the current passes through it, the filament heats up, and this produces light. So, this is how electrical energy is converted to light energy

The heat that is produced in the filament is more because of the high resistance of the filament which is why the bulb lights up

Moving on, there are some appliances where electrical energy is converted to heat energy

Let us take the example of an iron

The iron has a coil that has high resistance

When current passes through this coil, heat is produced because of which the plate gets heated up

So here electrical energy is converted into heat energy. This is how we can iron our clothes

Now, if we talk about a steam iron

Here, the water is converted into steam because of the heat produced by the coil

Other common examples for the heating effect would be an immersion rod and a fan heater

They also consist of coils that are heated up once electrical energy passes through them

REVISION

Whenever current flows through wires, some electrical energy is transformed into thermal energy called Joule heating

And the formula to calculate the heat released is

So more the current, resistance and the time for which the circuit is on, the more the heat is generated

Using this law, electrical energy is converted to heat energy in appliances like electric heaters and electric iron

Similarly, electrical energy is converted to light energy in appliances like an electric bulb

The End