Electric Dipole

When two equal and opposite charges are placed at a small distance, the combination is called a electric Dipole.

The strength of dipole is measured by Dipole Moment, a vector quantity, whose magnitude is equal to product of either charge and distance between the two charges and has the direction along the negative to positive charge.

Electric Field due to a Circular Ring of Charge—

Let us consider a circular ring of radius ‘a’ and total charge q is distributed over it.

            Let P be a point at a distance r from the centre of the ring and at the axis of ring, where electric field due to ring is to be determined.

Electric Field—

The electric field due to a charge is the space around the charge in which it exerts an electrostatic force on any other charge.

Electric Field Intensity—

The electric field intensity at a point due to a source charge may be defined as the force experienced per unit positive test charge placed at that point without disturbing the source charge.

Continuous Distribution of Charges--

When we consider the charged body of reasonable size, charge has continuous distribution. The continuous distribution of charge may be of one dimensional, two or three dimensional.

Linear Charge Density--

When charge is distributed along a line, the distribution is called linear.

If Charge q is distributed over the length L, then 

Linear charge density(λ) =q/l

Surface Charge Density--

When charge is distributed over the entire surface, the