On the strength of the Dirac monopole

A magnetic pole of strength g0is placed initially midway between two electrons of charge e. Consideration of the torque required to move one electron in a semicircular arc into coincidence with the other leads to an evaluation of the angular momentum thus added to the system as 2eg0/c. Since the eigenvalues of the angular momentum operator are spaced by h, go is clearly limited to n(hc/e2)e/2, the Dirac result. © 1977, American Association of Physics Teachers. All rights reserved.