Electrostatic Potential

Conservative Forces

When one form of energy gets converted to another completely on application or removal of external force, the forces are said to be conservative. Examples of conservative forces are sum of kinetic and potential energies working on a body, spring and gravitational force, coulomb force between two stationary charges, etc.

Work done in moving an object from one point to another depends only on the initial and final positions and is independent of the path taken.

Electrostatic Potential

o Electrostatic potential at a point is the work done by the external force in bringing a charge from infinity to that point.

The quantity of potential difference is more physically significant than actual value of potential energy.

W_RP = ΔU = U_P - U_R

(U_P +α) - (U_R +α) = U_P - U_R, the arbitrary α has no effect on potential energy difference

If the initial point is at infinity, W_∞P = ΔU = U_P - U_∞

U_∞ is usually considered as 0, so W_∞P = ΔU = U_P

Electric Potential and Potential Difference

Electric Potential:

The amount of electric potential energy at a point is called electric potential.

Electric Potential difference:

The difference in the amount of electric potential energy between two points in an electric circuit is called Electric potential difference.

Electric potential difference is known as voltage, which is equal to the work done per unit charge to move the charge between two points against static electric field.

There,

Voltage or electric potential difference is denoted by ‘V’. Therefore;

Where, W = work done and Q = Charge

SI unit of electric potential difference (Voltage):

SI unit of electric potential difference is volt and denoted by ‘V’. This is named in honour of Italian Physicist Alessandro Volta.

or

Since joule is the unit of work and coulomb is the unit of charge; 1 volt of electric potential difference is equal to the 1 joule of work to be done to move a charge of 1 coulomb from one point to another in an electric circuit. Therefore,

or