Question

What do you understand by the term ‘electric potential’ or (potential) at a point?What is the unit of electric potential?

Answer 1

To move a charge in an electric field we need to do work against the electrostatic force acting on the charge. Electric potential is an energy which is necessary to move a charge in an electric field. The work done against the force in moving a charge a more distance will be more and it also depends on the magnitude of the electric field.

Complete step by step answer:
When a unit positive charge is moved from infinity to a fixed point in the electric field the work done by external agents or the negative work done by electrostatic field during this process is equal to the potential at that point in the field.
${W_{ext}} = - q\int\limits_\infty ^P {\vec E.d\vec l}$
$V = \dfrac{{{W_{ext}}(0 \to P)}}{q}$
Then the potential at point P is given as:
${V_P} = - \int\limits_\infty ^P {\vec E.d\vec l}$
The unit of electric potential is Volt (V) which is $J{C^{ - 1}}$.

Note: Potential decreases in the direction of electric field. The difference of potential between any two points in an electric field is defined as the electric potential difference which is a scalar quantity and also known as voltage between the points. We can say that potential at a point is defined as the potential difference between the point and infinity.