Chapter-3|Current Electricity| NCERT 12th Physics:
If two bodies charged to different potentials are connected together by means of conducting wire, charges begin to flow from one body to another. The charges continue to flow till the potential of the two bodies become equal.
The flow of electric charges through a conductor constitutes an electric current.
It is defined as the rate of flow of electric charges through any cross section of a conductor. It is denoted by I.
If the current is steadily that is the rate of flow of current (charges) does not change with time, then
Electric current is not always steadily and hence more generally, we can define the current as follows.