The electric current is a flow of electric charges (called electrons) in a conductor such as a metal wire.
The SI unit of electric current is ampere.
A continuous conducting path consisting of wires and other resistances (like electric bulb, etc.) and a switch, between the two terminals of a cell or a battery along which an electric current flows, is called a circuit.
According to Ohm’s law : At constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends.
The electrical resistance of a conductor (or a wire) depends on the following factors :
(i) length of the conductor,
(ii) area of cross-section of the conductor (or thickness of the conductor),
(iii) nature of the material of the conductor, and
(iv) temperature of the conductor.
When an electric current is passed through a high resistance
wire, like nichrome wire, the resistance wire becomes very hot
and produces heat. This is called the heating effect of current.