Electric Current

Chapter-3|Current Electricity| NCERT 12th Physics:
Electric Current:
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.

Let Δq be the net charge flowing through a cross-section of the conductor in time t to t+Δt, then the current I at any time t is given by
Current is a scalar quantity because it does not follow the law of vector addition.
The SI unit of current is ampere (A).
Definition Of Ampere:
If one coulomb of charge crosses an area in one second, then the current through that area is 1 ampere.

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