The modern revolution in physics

132 Pages·2000·1.546 MB·English

by  Benjamin Crowell

The Modern
Revolution in Physics
Benjamin Crowell
Book 6 in the Light and Matter series of introductory physics textbooks
www.lightandmatter.com

The Modern
Revolution
in Physics
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
The Modern Revolution
in Physics
Benjamin Crowell
www.lightandmatter.com
Light and Matter
Fullerton, California
www.lightandmatter.com
© 2000 by Benjamin Crowell
All rights reserved.
Edition 2.0
rev. 2002-06-03
ISBN 0-9704670-6-0
Brief Contents
1 Relativity, Part I 11
2 Relativity, Part II 29
3 Rules of Randomness 45
4 Light as a Particle 63
5 Matter as a Wave 77
6 The Atom 97
Contents
1 Relativity, Part I 11
1.1 The Principle of Relativity.................... 12
1.2 Distortion of Time and Space .............. 13
1.3 Applications ......................................... 20
Summary...................................................... 26
Homework Problems.................................... 27
3 Rules of Randomness45
3.1 Randomness Isn’t Random ................. 46
3.2 Calculating Randomness..................... 47
3.3 Probability Distributions....................... 50
3.4 Exponential Decay and Half-Life ......... 53
2 Relativity, Part II 29 3.5(cid:242) Applications of Calculus ..................... 58
Summary...................................................... 60
2.1 Invariants............................................. 30
Homework Problems.................................... 61
2.2 Combination of Velocities.................... 30
2.3 Momentum and Force ......................... 32
2.4 Kinetic Energy ..................................... 33
2.5 Equivalence of Mass and Energy........ 35
2.6* Proofs................................................. 38
Summary...................................................... 40
Homework Problems.................................... 41
4 Light as a Particle 63
4.1 Evidence for Light as a Particle........... 64
4.2 How Much Light Is One Photon?......... 65
4.3 Wave-Particle Duality .......................... 69
4.4 Photons in Three Dimensions ............. 73
Summary...................................................... 74
Homework Problems.................................... 75
6 The Atom 97
6.1 Classifying States................................ 98
6.2 Angular Momentum in Three Dimensions
99
6.3 The Hydrogen Atom........................... 101
6.4* Energies of States in Hydrogen ....... 104
6.5 Electron Spin ..................................... 106
6.6 Atoms With More Than One Electron 107
Summary.................................................... 109
Homework Problems...................................110
5 Matter as a Wave 77
5.1 Electrons as Waves............................. 78
5.2*(cid:242) Dispersive Waves.............................. 82
5.3 Bound States....................................... 84
5.4 The Uncertainty Principle and
Measurement.......................................... 86
5.5 Electrons in Electric Fields .................. 90
5.6*(cid:242) The Schrödinger Equation ................ 91
Summary...................................................... 94
Exercises 113
Homework Problems.................................... 95
Solutions to Selected
Problems 117
Glossary 119
Index 121
Photo Credits 125