10.10 Experiments
Experiment 1 (The Electromagnetic Brake. Demonstrates: Induced Currents Due to Motion, Electromotive Force,
Lenz’s Law, Faraday’s Law of Induction). The principle of the electromagnetic brake can be demonstrated with a strong
magnet and a thick conducting plate. A suitable magnet is a magnet with a small gap between its poles. Two large
loudspeaker magnets placed so that the opposite poles are located on two sides of the gap can be used. Figures 10.32a
and 10.32b show two possible configurations.
The conducting plate can be a simple aluminum plate. It should be at least 5 mm thick (the thicker the better) and 200 mm
wide. A hole is drilled in the plate so that it can be suspended freely. A pencil may be passed through the hole to create a pivot.
Lift the plate and allow it to swing through the gap between the twomagnets. Notice the retarding effect of the magnet. If the
magnet is strong, and the plate thick, the plate should come to an almost complete stop within the gap.Otherwise, itwill oscillate
somewhat and then stop. An alternative is to simply drop the aluminumplate between the poles and observe itsmotion. The same