Electricity and Magnetism

Book 4 in the Light and Matter series of free introductory physics textbooks
www.lightandmatter.com

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The Light and Matter series of
introductory physics textbooks:
1 Newtonian Physics
2 Conservation Laws
3 Vibrations and Waves
4 Electricity and Magnetism
5 Optics
6 The Modern Revolution in Physics

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Benjamin Crowell
www.lightandmatter.com

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Fullerton, California
www.lightandmatter.com
copyright 1999-2008 Benjamin Crowell
rev. April 5, 2010
This
book
is
licensed
under
the
Creative
Com-
mons
Attribution-ShareAlike
license,
version
3.0,
http://creativecommons.org/licenses/by-sa/3.0/, except
for those photographs and drawings of which I am not
the author, as listed in the photo credits. If you agree
to the license, it grants you certain privileges that you
would not otherwise have, such as the right to copy the
book, or download the digital version free of charge from
www.lightandmatter.com.
ISBN 0-9704670-4-4

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To Arnold Arons.

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Brief Contents
1 Electricity and the Atom
13
2 The Nucleus
41
3 Circuits, Part 1
77
4 Circuits, Part 2
107
5 Fields of Force
125
6 Electromagnetism
145
A Capacitance and Inductance
171

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Contents
1 Electricity and the Atom
Isotopes, 55.—Sizes and shapes of nuclei,
56.
1.1 The Quest for the Atomic Force . .
14
2.5 The Strong Nuclear Force, Alpha De-
1.2 Charge, Electricity and Magnetism .
15
cay and Fission. . . . . . . . . . .
56
Charge,
15.—Conservation
of
charge,
17.—Electrical forces involving neutral
Randomness in physics, 59.
objects,
18.—The
path
ahead,
18.—
2.6 The Weak Nuclear Force; Beta Decay 59
Magnetic forces, 18.
The solar neutrino problem, 61.
1.3 Atoms . . . . . . . . . . . . .
20
2.7 Fusion. . . . . . . . . . . . .
63
Atomism, 20.—Atoms, light, and every-
2.8 Nuclear Energy and Binding Energies 64
thing else, 22.—The chemical elements,
2.9 Biological
Effects
of
Ionizing
23.—Making sense of the elements, 24.—
Radiation . . . . . . . . . . . . .
67
Direct proof that atoms existed, 25.
2.10
The Creation of the Elements . .
71
1.4 Quantization of Charge. . . . . .
26
Creation of hydrogen and helium in the Big
1.5 The Electron . . . . . . . . . .
30
bang, 71.—We are stardust, 71.—Artificial
Cathode rays, 30.—Were cathode rays
synthesis of heavy elements, 72.
a form of light, or of matter?, 30.—
Summary . . . . . . . . . . . . .
73
Thomson’s experiments, 31.—The cathode
Problems . . . . . . . . . . . . .
75
ray as a subatomic particle: the electron,
33.
1.6 The Raisin Cookie Model of the Atom 34
Summary . . . . . . . . . . . . .
37
Problems . . . . . . . . . . . . .
39
3 Circuits, Part 1
3.1 Current . . . . . . . . . . . .
78
Unity of all types of electricity, 78.—
Electric current, 79.
3.2 Circuits . . . . . . . . . . . .
81
3.3 Voltage . . . . . . . . . . . .
82
The volt unit, 82.—The voltage concept in
general, 83.
3.4 Resistance . . . . . . . . . . .
87
2 The Nucleus
Resistance, 87.—Superconductors, 89.—
2.1 Radioactivity . . . . . . . . . .
41
Constant voltage throughout a conductor,
Becquerel’s
discovery
of
radioactivity,
90.—Short circuits, 91.—Resistors, 91.—
41.—Three kinds of “radiations”, 43.—
Lightbulb,
92.—Polygraph,
92.—Fuse,
Radium:
a
more
intense
source
of
92.—Voltmeter, 93.
radioactivity, 43.—Tracking down the na-
3.5 Current-Conducting
Properties
of
ture of alphas, betas, and gammas, 43.
Materials . . . . . . . . . . . . .
94
2.2 The Planetary Model of the Atom .
45
Solids,
94.—Gases,
95.—Liquids
and
Some phenomena explained with the plan-
plasma, 96.—Speed of currents and elec-
etary model, 48.
trical signals, 96.
2.3 Atomic Number . . . . . . . . .
48
3.6
Applications of Calculus . . . .
98
2.4 The Structure of Nuclei. . . . . .
53
Summary . . . . . . . . . . . . . 100
The proton,
53.—The neutron,
54.—
Problems . . . . . . . . . . . . . 102
10

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