College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 77

An electron moves in a circular path perpendicular to a constant magnetic field of magnitude 1.00 mT. The angular momentum of the electron about the center of the circle is 4.00 × 10 25 kg · m 2 /s. Determine (a) the radius of the circular path and (b) the speed of the electron.