WEBVTT

00:00.000 --> 00:08.159
Now, we will try to understand
the concept of electric current

00:08.159 --> 00:17.000
For that, we will first try to visualize the
basic structure of atom of a metallic conductor

00:17.000 --> 00:25.280
Basic nature of metal is that, its atom consists
of loosely bonded electrons in its outermost cell

00:25.280 --> 00:32.000
This electron is so loosely bonded with the
parent atom that anytime due to a tiny energy

00:32.000 --> 00:37.639
it may detach from the parent atom.
This electron is called free electron

00:37.639 --> 00:50.340
A free electron randomly moves here and there inside the metal. Again, when
it gets vacant orbit in other atom, it may associate with that atom but

00:50.340 --> 00:59.099
does not stay there permanently, means after some
time it may again detach from that atom also

00:59.099 --> 01:04.860
In this way, free electron is detached from
atom and after moving randomly inside the

01:04.860 --> 01:12.680
metal body, it associates with another
atom and again is detached from there

01:12.680 --> 01:18.660
A metal has plenty of these free electrons
inside it even at room temperature

01:19.660 --> 01:25.080
Now, if this metal conductor is connected
across a voltage source, these free electrons

01:25.080 --> 01:31.080
come under an electric field and
an electric force acts on them

01:31.080 --> 01:36.379
As the electrons are electronegative, they
will be accelerated towards the positive end

01:36.379 --> 01:47.120
of the conductor. As a result, these free electrons
drift towards the positive end of the metal conductor

01:47.120 --> 01:52.080
As these electrons have negative electrical
charge, there is a flow of negative charge

01:52.080 --> 02:01.919
towards the positive end of the metal conductor. The flow of negative
charge from negative to positive terminal of the conductor can

02:01.919 --> 02:07.839
be alternatively assumed as flow of positive
charge from positive to negative terminal

02:07.839 --> 02:16.559
of the conductor. And the rate of flow of positive
charge in respect of time from higher potential terminal

02:16.720 --> 02:22.320
i.e. positive terminal to lower potential
terminal or negative terminal of a conductor

02:22.320 --> 02:32.399
is defined as electric current. So hope we get a clear
concept of electric current through a metal conductor

02:32.399 --> 02:33.080
Thank you