AN EXPERIMENT ON MAGNETIC INDUCTION PULSES

The voltage pulse induced by a bar magnet as it moves at constant velocity through the axis of a circular coil is analyzed. The physical system considered has a number of interesting features: (a) It is easy to set up and handle in the laboratory, (b) the observed pulse can be predicted theoretically by means of a simple model, and (c) it provides a very vivid and direct illustration of the concept of electromagnetic induction. In fact, the system of a coil and magnet in relative motion is usually presented in textbooks when introducing this concept. The experiment can also be used as a procedure for determining the magnetic dipole moment of magnets. Since the equipment, a digital storage oscilloscope or computer, is usually available in undergraduate laboratories, the experiment can be performed in the introductory physics course.