Chapter study guide

Electricity and magnetism were considered two different phenomena until 1820, when the Danish physicist Hans Christian Ørsted discovered the connection between them. Moving charged particles, such as electric current in a wire, create a magnetic field around them. Changing magnetic flux, such as through a loop of wire, generates electric current in the wire. Electromagnetism lies at the heart of many technologies, such as the electromagnet, electric motor, generator, and transformer.

By the end of this chapter you should be able to
describe and investigate the connection between electricity and magnetism;
describe key scientists and their contributions to the field of electromagnetism;
describe how an electromagnet works and determine its polarity;
list technologies based on electromagnetism;
define magnetic flux and describe magnetic induction;
describe the components and operation of an electric motor and generator;
calculate the magnetic force on a moving charged particle and its cyclotron radius;
calculate the forces felt by two current-carrying wires and a wire loop rotating in a magnetic field; and
describe the principles behind the mass spectrometer, galvanometer, and cathode ray tube.

19A: Build an electromagnet
19B: Electric motor

552Magnetic fields and the electric motor
55419A: Build an electromagnet
555Electric motors
55619B: Electric motor
557Inside an electric motor
558Design a Rube Goldberg machine
559Section 1 review
560Induction and the generator
561Induction by changing magnetic fields
562Electric generators
564Section 2 review
565Magnetic fields and moving charges
566Mass spectrometer
567Magnetic force around a current-carrying wire
568Magnetic force on a current-carrying wire
57019C: Build a paper clip motor
571Other applications of electromagnetism
572Hybrid cars
573Operating a hybrid car
574Section 3 review
575Chapter review
Φ B =BAcosθ
emf=N Δ Φ B Δt
V s V p = N s N p
F B =qvBsinθ
B= μ 0 I 2πr
solenoidelectric motorcommutator
armaturemagnetic fluxFaraday’s law of induction
electromagnetic inductionLenz’s lawelectrical generator
transformermass spectrometercyclotron radius
permeability of free spacevoice coilgalvanometer
cathode ray tube (CRT)

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