Lecture 5
Def. Dipole - An e dipole is formed by 2 +/- point charges, +q/-q
ElDipole moment, Cm
See Figure 8 in notes
Field of an electric dipole
Potential from superpositon - see Eqn 53
Considering the far field limit [r>>a], use Taylor expansion to get Eqn 54, the far-field limit of potential, which is a solution of the Laplace eqn [div^2]
For electric field, use the gradient identity as seen in Eqn 55. It's components are simplest in spherical coords (see Eqn 56)
Ideal Dipole - limit a->0,q->infinity with p=constant
Physical dipole - fill solution see eqn 57
The sketches (F9) for these electric fields are slightly different
Dipole Interaction with the External Electric FIeld
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Multipole Expansions
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