Question

write an expression for equivalent magnetic moment of plane current loop of area A, having N turns and carrying a current i.use this expression to find the magnetic dipole moment of revolving electron.

Answer 1

m=niA

For a revolving electron,

I=q/t = e/T = e/2pier/v = ev/2pie r

So, m=N(ev/2pie r)*pie r^2= N(evr/2)

Answer 2

For equivalent magnetic moment of plane current loop of area A, having N-turns and carrying a current is, m= ANi

For a revolving electron the equation is,

m= N(evr/2)

Image is provided below for more conceptual clearance.