Electric field of an electric dipole
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Total charge of an electric dipole is zero but since the charges are separated by some distance the electric field do not cancel out.
Dipole moment is the mathematical product of the separation of the ends of a dipole and the magnitude of the charges( 2a x q).
Some molecules like H 2 O, have permanent dipole moment as their charges do not coincide. These molecules are called polar molecules.
Permanent dipoles have a dipole moment irrespective of any external Electric field.
Electric field of an electric dipole
Electric field of an electric dipole at a point in space depends upon the position of the point.
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The dipole field at a point is inversely proportional to the cube of distance from the center to the point.
For a very small dipole, the 2a approaches zero. This is called point dipole.