Question

Electric current always flows from………to…………

Answer 1

Hint: In order to solve this question we need to understand what is current and how it flows and why we need to detect or measure it. So current is a scalar quantity and it is defined as the number of charges crossing a unit area in unit interval of time. Its direction is opposite to the flow of electrons. So when a wire is subjected to potential difference then an electric field is set up in the wire which binds the electrons to flow in the opposite direction of the electric field and hence current flows in the same direction as the electric field. We need to detect it so that we can have a control over it and we measure it to find resistance in the wire.

Complete answer:
Now suppose a wire is subjected to electric potential difference having high potential in the left side and low potential in right side. Then we know electric fields produced in wire always have a direction in decreasing potential. So the electric field flows from left to right. Hence it exerts force on free electrons in the left, due to this electron starts flowing from right to left.

Consider a unit cross sectional area of wire and electrons pass through it from right to left, let in time “t” “ne” amount of electrons passes then electric current is given by,
$i = \dfrac{{ - ne}}{t}$
Here the $ - ve$ sign indicates that current flows in the opposite direction of electron flow.

So electric current flows from High potential to low potential.

Note: It should be remembered that besides having magnitude and direction of current it is scalar quantity because current cannot be added by triangle law of vector addition so it is a scalar quantity. At the junction, the amount of current entering must leave the junction by the same amount because according to the equation of continuity no charge can accumulate at the junction.