Chapter 28, Problem 39P

(a)

To determine

The magnetic dipole moment of the non-conducting circular disk.

(b)

To determine

The magnetic field at points on its axis a distance $x$ from its center.

(c)

To determine

Whether $B\approx \frac{{\mu }_0}{2\pi }\frac{\mu }{x^3}$ is applicable for the case $x\gg R$.