Physics: Principles with Applications (7th Edition)

Published by Pearson
ISBN 10: 0-32162-592-7
ISBN 13: 978-0-32162-592-2

Chapter 19 - DC Circuits - General Problems - Page 557: 85

Answer

See answers.

Work Step by Step

a. Assume that the ammeter has zero resistance and that the voltmeter has resistance $R_V$. Use Ohm’s law with the equivalent resistance. The voltmeter is reading the voltage across the battery. $$V=IR_{eq}=I\frac{1}{\frac{1}{R}+\frac{1}{R_V}}$$ $$V(\frac{1}{R}+\frac{1}{R_V})=I$$ $$(\frac{1}{R}+\frac{1}{R_V})=\frac{I}{V}$$ $$\frac{1}{R}=\frac{I}{V}-\frac{1}{R_V}$$ b. Assume the voltmeter has infinite resistance and that the ammeter has resistance $R_A$. Use Ohm’s law with the equivalent resistance. The voltmeter is reading the voltage across the battery. $$V=IR_{eq}=I(R+R_A)$$ $$ (R+R_A)=\frac{V}{I}$$ $$ R=\frac{V}{I}-R_A$$
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.