Conceptual Physics (12th Edition)

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

Chapter 25 - Think and Do: 31


This is a writing exercise for the student, and answers will vary.

Work Step by Step

Hey Keon, I finally found out the answer to a puzzle that has bugged people for centuries - what is light? It turns out it is a wave, but unlike water waves or sound waves, it doesn't require a medium, and can even travel through vacuum. Light is an electromagnetic wave, and it sustains itself. A changing electric field creates a changing magnetic field, and a changing magnetic field creates a changing electric field. The two fields carry themselves and each other along in this way, traveling at an incredible 299,792,458 m/s through outer space. That's what light is. Who knew?
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