PHYS208 Fundamentals of Physics II

Hint for Ch. 23, 25P

Remember the geometry that I set up for the conjugate pairs in the case of the charged ring. Switch to opposite charges and adjust the E contributions accordingly.

First Hint for Ch. 23, special problem

Consider charge elements that are conjugate about the perpendicular bisector of P. The contribution to E from the negative and positive infinitesimal elements will combine to point down, horizontal components cancelling. The result for the point dipole (Ch. 23: 25P) can be used for the conjugate pair and the linear charge density integrated from 0 to a.

Second Hint for Ch. 23, special problem

If you span the charge distribution as shown, the following integral should result...

[dipole lines]

[dipole lines]

with the direction of E downward.

Last updated Feb. 27, 1998.
Copyright George Watson, Univ. of Delaware, 1997.