Asked by Anonymous

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?
Answered by bobpursley
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