2005/01/03 | 电偶极子[Electric Dipole]
类别(Ω〖物理〗) | 评论(0) | 阅读(65) | 发表于 14:58
In cgs, the electric dipole potential of a dipole with electric dipole moment p is given by
(1)

where r is the distance from the dipole. In MKS,
(2)

where is the permittivity of free space.

In polar coordinates, the electric field of an electric dipole in cgs is
(3)

(4)

and in MKS,
(5)

(6)

Doing a coordinate-independent calculation in cgs units,

(7)



(8)

Because p is a constant vector
(9)

(10)

Plugging (8), (9), and (10) into (7),
(11)

Therefore, in cgs,
(12)

and in MKS,
(13)

Then the force exerted by an imposed electric field E on the dipole is
(14)

Let two dipoles and be at angles and measured from the line connecting the dipoles. Then the energy of interaction is


where is the azimuth of relative to the plane.
The torque exerted on a dipole of dipole moment p in an electric field E is
(15)

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