Define electric potential and explain it. Write its SI unit and give its other units.

Explanation

The work required to be done against the electric field to bringa unit positive charge from infinite distance to the given point in the electric field is called the electrostatic or electric potential at that point. It is indicate by .V.

Consider a positive charge Q at the origin O and point P at certain distance and point R at infinite distance from its electric field.
Work done in brininga unit positive charge from infinity to the point P is the potential energy of that charge. Hence, work done by an external force in bringing a unit positive charge without acceleration from infinity to a point is the electrostatic potential at that point.

For this definition two remarks should kept in mind:
(1) Work done on a test charge q by the electrostatic field due to any given charge| configuration is independent of the path and depends only on its initial and final positions .
(2) To obtain the work done per unit test charge, we should take an infinitesimal test charge `deltaq` obtain the work done `deltaW` in bringing it from infinity to the point and determine the ratio `(deltaW)/(deltaq)` . The external force at every point of the path is to be equal and opposite to the electrostatic force on the test charge at that point.
Electric potential is a vector quantity. Its SI unit is `(J)/(C )` or Volt V in memory of the sclentist Volta.
Other units `: V=(I)/(C )=(Nm)/(C)=(Wb)/(C)=(Wb)/(S)=(Tm)/(A)`
and dimensional formula : `[ M^(1)L^(2)T^(-3)A^(-1)]`