Question

Define the term 'electric dipole moment'. Show that for a given short electric dipole
the electric field intensity at far point, from the center of the dipole, on axial line is
almost twice that of electric field intensity at the same point on equatorial line.
(5 marks)​

Answer 1

Explanation:

The electric field due to a point dipole (upper left), a physical dipole of electric charges (upper right), a thin polarized sheet (lower left) or a plate capacitor (lower right). All generate the same field profile when the arrangement is infinitesimally small.

The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system, that is, a measure of the system's overall polarity. The SI units for electric dipole moment are coulomb-meter (C⋅m); however, a commonly used unit in atomic physics and chemistry is the debye (D).

Theoretically, an electric dipole is defined by the first-order term of the multipole expansion; it consists of two equal and opposite charges that are infinitesimally close together. This is unrealistic, as real dipoles have separated charge.[1] However, when making a measurement at a distance that is much larger than the charge separation, the error introduced by treating real dipoles like they are theoretically perfect becomes negligible. By definition, the dipole's direction points from the negative charge towards the positive charge.