Induction and Alternating Current with teacher's notes
Chapter 22 Overview Section 22-1 introduces induced current, discusses Lenz’s law, and applies Faraday’s law of induction to calculate induced emf and induced current. Section 22-2 introduces generators and motors as devices that convert energy from one form to another and shows how to calculate the maximum emf for an electrical generator, the rms current, and the potential difference for ac circuits. Section 22-3 examines mutual induction, discusses transformers, shows how to calculate the potential difference for a step-up or step-down transformer, and describes how self-induction occurs in a circuit. About the Illustration The strings of an electric guitar are magnetized by a permanent magnet located inside coils of wire beneath the strings. Two sets of coils—one at the base of the neck and the other just above the bridge—can be seen in each of the guitars in the photograph. As a string vibrates, the changing magnetic field induces in the coil an alternating current, whose frequency depends on the string’s frequency. Interactive Problem- Solving Tutor See Module 20 “Induction and Transformers” promotes additional development of problem-solving skills. 792 DTSI Graphics HRW—Holt Physics 2002 Page 792 CMYK Copyright © by Holt, Rinehart and Winston. All rights reserved.