In Fig. [104], the loop (A) has gone beyond the influence of the magnetic field, and now the current in the loop tries to return, or reverse itself, as shown by the dart (D). It is a reaction that causes the current to die out, so that when the loop has reached the point farthest from the magnet, as shown in Fig. [105], there is no current in the loop, or, if there is any, it moves faintly in the direction of the dart (E).
Current Reversing Itself.—When the loop reaches its lowest point (Fig. [106]) it again comes within the magnetic field and the current commences to flow back to its original direction, as shown by darts (C)
Self-Induction.—This tendency of a current to reverse itself, under the conditions cited, is called self-induction, or inductance, and it would be well to keep this in mind in pursuing the study of alternating currents.
You will see from the foregoing, that the alternations, or the change of direction of the current, depends upon the speed of rotation of the loop past the end of the magnet.
