Thu June 30, 2011 By: Archna Khatri

does electric feild and electric dipole have same direction on the axis if a positive and a negative charges of equal magnitude are kept on the axis? please explain in detail

Expert Reply
Fri July 01, 2011
The direction of electric dipole moment is always from negative charge to positive charge and on calculation the direction of electric field has also been found to be along the same line for points on axial line.

Electric field produced by a dipole is known as dipole field.

Let +q and -q be equal and opposite point charges separated by a small distance 2l. The strength of an electric dipole is measured by a vector quantity known as electric dipole moment known as electric dipole moment , which is the product of the charge and separation between the charges, that is

The direction of is always from negative to positive. The SI unit of dipole movement is Coulomb-meter.

(a) For points on axial line

line of a dipole is the line passing through the positive and negative charges of the electric dipole.

Consider a system of charges (-q and +q) separated by a distance 2a. Let 'P' be any point on an axis where the field intensity is to be determined.

Electric field at P (EB) due to +q

Electric field at P due to -q (EA)

Net field at P is given by

Simplifying, we get

Thu May 04, 2017


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