Physics Technology Update (4th Edition)

Published by Pearson
ISBN 10: 0-32190-308-0
ISBN 13: 978-0-32190-308-2

Chapter 21 - Electric Current and Direct-Current Circuits - Problems and Conceptual Exercises - Page 756: 32

Answer

a) $I=0.79A$ b) $R=120.33\Omega$ c) If the resistance is halved then the power will be doubled.

Work Step by Step

(a) We know that $P=VI$ This can be rearranged as: $I=\frac{P}{V}$ We plug in the known values to obtain: $I=\frac{75}{95}$ $I=0.79A$ (b) As $P=\frac{V^2}{R}$ This can be rearranged as: $R=\frac{V^2}{P}$ We plug in the known values to obtain: $R=\frac{(95)^2}{75}$ $R=120.33\Omega$ (c) We know that $P=\frac{V^2}{R}$ According to given condition $R^{\prime}=\frac{R}{2}$ $\implies P=\frac{V^2}{R\prime}$ $\implies P=\frac{V^2}{\frac{R}{2}}=2\frac{V^2}{R}=2P$ Thus, if the resistance is halved then the power will be doubled.
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.