Conceptual Physics (12th Edition)

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

Chapter 20 - Think and Explain - Page 389-390: 66


The sound intensity decreases by a factor of 9.

Work Step by Step

The inverse-square law predicts that the intensity would be $\frac{1}{9}$ its original value if the distance to the source were tripled. The outgoing sound power is distributed over the surface of a sphere with 9 times the area of the original sphere, so the received power per unit area (intensity) is one-ninth of its previous value.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.