Conceptual Physics (12th Edition)

Published by Addison-Wesley
ISBN 10: 0321909100
ISBN 13: 978-0-32190-910-7

Chapter 25 - Think and Explain - Page 482-483: 62


The trick is based on electromagnetic induction.

Work Step by Step

When the switch is flipped, the newly formed field induces a current in the aluminum ring (as explained by Faraday's Law). This current generates a magnetic field, momentarily making the aluminum ring into a bar magnet. The ring's field opposes the original field produced by the hidden electromagnet. The aluminum ring is repelled into the air.
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