What is Joule's heating effect ? How can it be demonstrated experimentally ? List its four applications in daily life.

Explanation

The heating effect of current is defined by Joules law of heating. It states that the heat H produced by a resistor of resistance R due to current flowing through it for time t is `H = I^(2)Rt`. It is also called ohmic heating and resistive heating.
In a conductor when an electric field is applied across its ends, the free electrons available in it start drifting opposite to the direction of the electric field. These electrons collide with the atoms which have lost the electrons.
As a result of these collisions some energy of the electrons is transferred to the atoms which vibrate violently as they gain energy. Thus, heat is developed in the conductor. Greater the current, greater will be the rate of collision and so greater will be the heat produced.
The four applications using heating effect of current are as follows
(i) room heater (ii) electric bulb
(iii) electric iron (iv) electric fuse