Q. Illustrate Electric Potential and Voltage?

When electrical forces act on a particle, it will possess potential energy. In order to describe the potential energy that a particle will have at a point x, the electric potential at point x is defined as

where w(x) is the potential energy that a particle with charge q has when it is located at the position x. The zero point of potential energy can be chosen arbitrarily since only differences in energy have practicalmeaning. The pointwhere electric potential is zero is known as the reference point or ground point, with respect to which potentials at other points are then described. The potential difference is known as the voltage expressed in volts (V) or joules per coulomb (J/C).

If the potential at B is higher than that at A,

v_BA = v_B - v_A

which is positive.Obviously voltages can be either positive or negative numbers, and it follows that

v_BA =-v_AB

The voltage at point A, designated as vA, is then the potential at point A with respect to the ground.