Chapter 24, Problem 99P

(a) Using Eq. 24-32, show that the electric potential at a point on the central axis of a thin ring (of charge q and radius R) and at distance z from the ring is

$V=\frac{1}{4\pi {\text{ε}}_{\text{0}}}\frac{q}{\sqrt{z^2+R^2}}.$

(b) From this result, derive an expression for the electric field magnitude E at points on the ring’s axis; compare your result with the calculation of E in Module 22-4.

Figure 24-71 Problem 98.