In hydrogen atom, an electron of charge ' e ' revolves in an orbit of radius ' r ' with speed ' v '. The magnetic moment associated with electron is

Step-by-step solution

The magnetic moment of a current loop is given by = IA , where I is the current and A is the area enclosed. For an electron with charge e revolving in a circular orbit of radius r with speed v , the current is I = e T = e 2 r/v = ev 2 r . The area is A = r^2 . Substituting these expressions yields = ( ev 2 r ) ( r^2 ) = evr 2 . The magnetic moment is therefore evr 2 , corresponding to option B.