Chapter-4|Moving Charges and Magnetism| NCERT 12th Physics:
Magnetic Dipole Moment of a Revolving Electron (For Hydrogen Like Atom):
Let an electron(e⁻) is revolving in a loop(atom), mass m, velocity v and radius r.
When electron (e⁻) revolve around nucleus, it constitute a current.
Since, q= It, therefore I= q/t = e⁻/t.