1. The problem statement, all variables and given/known data In a model of a hydrogen atom, an electron circles the proton at a distance of 5.29E-11 m with a speed of 2.19E6 m/s. Compute the magnitude of the magnetic field that this motion produces at the location of the proton. 2. Relevant equations dB = (u/4pi*r^2) I ds x r(roof) (Biot-Savart's law) 3. The attempt at a solution I did I = e*v/(2*pi*r) where e is electron charge and v is the velocity. I got I = .00105 A. I plug in that into B = uI/(4*pi*r) = 1.99 T but the answer is 12.5 T. What am I doing wrong? Thank you.