Experiment 2 (The generator. Demonstrates: Electromotive Force, Induction, AC Generation, Lenz’s Law,
Faraday’s Law). The principle of induction can be demonstrated by using a permanent magnet as the source of the
magnetic field and a coil. A loudspeaker magnet is suitable for this purpose. Use a coil with an iron core and a large number
of turns. A low-voltage relay coil is suitable. Connect two light-emitting diodes (LEDs) across the leads of the coil as shown
in Figure 10.33. The diodes are connected in opposition, such that one diode lights up when the electromotive force is of one
polarity, the other when it has an opposite polarity. Use of two different color diodes will allow you to distinguish between
polarities of the electromotive force induced in the coil. Move the coil across the magnet, as close as possible to the magnet.
As the coil is moved in one direction, one diode lights up. Move the coil toward the magnet and away from the magnet. The
diodes will light up alternately. If the magnet is strong, the iron core will tend to stick. You can reduce this by placing a piece
of cardboard on the magnet and sliding the coil on the cardboard or sliding the magnet beneath the cardboard.