A two-level magnetic system is modelled by means of a 1/2-angular momentum with arbitrary orientation and its interaction with a periodic external magnetic field is considered (Rabi-like problem). Drawing on Schwinger's treatment of a similar problem, we apply the results to the emitted radiation and the absorbed power. It is shown that, owing to the continuous oscillations of the magnetization, the emission is one stimulated by the driving field, the coherent signal being enhanced.