Electric Potential :-

Electric Potential

When a body is charged, work is done in charging it. This work done is stored in the body
in the form of potential energy. The charged body has the capacity to do work by moving other
charges either by attraction or repulsion. The ability of the charged body to do work is called electric
potential. The capacity of a charged body to do work is called its electric potential.
The greater the capacity of a charged body to do work, the greater is its electric potential.
Obviously, the work done to charge a body to 1 coulomb will be a measure of its electric potential
i.e. Electric potential, V =Work done/Charge = W/Q
The work done is measured in joules and charge in coulombs. Therefore, the unit of electric
potential will be joules/coulomb or volt. If W = 1 joule, Q = 1 coulomb, then V = 1/1 = 1 volt.
Hence a body is said to have an electric potential of 1 volt if 1 joule of work is done to
give it a charge of 1 coulomb. Thus, when we say that a body has an electric potential of 5 volts, it means that 5 joules of work has been done to charge the body to 1 coulomb. In other words, every coulomb of charge possesses an energy of 5 joules. The greater the joules/coulomb on a charged body, the greater is its electric potential.

Potential Difference

The difference in the potentials of two charged bodies is called potential difference.

If two bodies have different electric potentials, a potential difference exists between the bodies. Consider two bodies A and B having potentials of 5 volts and 3 volts respectively  Each coulomb of charge on body A has an energy of 5 joules while each coulomb of charge on body B has an energy of 3 joules. Clearly, body A is at higher potential than the body B.

If the two bodies are joined through a conductor [See Fig. 1.6 (ii)], then electrons will *flow

from body B to body A. When the two bodies attain the same potential, the flow of current stops. Therefore, we arrive at a very important conclusion that current will flow in a circuit if potential difference exists. No potential difference, no current flow. It may be noted that potential difference is sometimes called voltage.

Unit. Since the unit of electric potential is volt, one can expect that unit of potential difference

will also be volt. It is defined as under :

The potential difference between two points is 1 volt if one joule of work is **done or released in transferring 1 coulomb of charge from one point to the other.