All Problems

Constant Magnetic Field, Magnetics

Problem 3.246

A non-conducting thin disc of radius \(R\) charged uniformly over one side with surface density \(\sigma\) rotates about its axis with an angular velocity \(\omega .\) Find: (a) the magnetic induction at the centre of the disc; (b) the magnetic moment of the disc.

Reveal Answer
 (a) B=1/2μ0σωR; (b) pm=1/4πσωR4 . \text { (a) } B=1 / 2 \mu_{0} \sigma \omega R ; \text { (b) } p_{m}=1 / 4 \pi \sigma \omega R^{4} \text { . }