Consider a nonconducting disc of radius `r` and mass `m` which has a total charge `q` distributed unifromly on it.The ring is rotated about its axis with an angular speed `omega`.(a) The equivalent electric current in the ring is `(qomega)/(Npi)`.Then find value of `N` (b) The magnetic moment of the ring is `(4qomegar^(2))/N`.Then find value of `N`.

Answer

A, B

Explanation

`i=qf={:(qomega),(2pi):}`
`M=pir^(2)i`
`pir^(2)={:(qomega),(2pi):}`
`=(qomegar^(2))/2`