An electron orbits a proton at a radius of 5.38 10-11 m. What is the magnitude of the magnetic field at the proton due to the orbital motion of the electron?

Answer 1

Oliver Heaviside, in 1888, first solved this question for moving charges.

B=mu*q/4PI * v/r^2

http://bama.ua.edu/~stjones/puzzles.htm