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: 80

Answer

50.6 volts is the emf, and 1.2 ohms is the internal resistance.

Work Step by Step

Equation 19-1 relates the emf, the current, and the terminal voltage. $$V=\epsilon-Ir$$ We are given information about the terminal voltage and the current in 2 situations. $$V_1=\epsilon-I_1r$$ $$V_2=\epsilon-I_2r$$ Solve these 2 equations simultaneously for the two unknowns. $$\epsilon=V_1+I_1r=V_2+I_2r$$ $$r=\frac{V_2-V_1}{I_1-I_2}=\frac{47.3V-40.8V}{8.40A-2.80A}\approx 1.2\Omega$$ $$\epsilon=V_1+I_1r=40.8V+(8.40A)(1.161\Omega)=50.6V$$
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.