The Britannica Guide to Sound and Light

367 Pages·2011·15.42 MB·English

by  Erik Gregersen

Published in 2011 by Britannica Educational Publishing
(a trademark of Encyclopædia Britannica, Inc.)
in association with Rosen Educational Services, LLC
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First Edition
Britannica Educational Publishing
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Introduction by Jennifer Capuzzo
Library of Congress Cataloging-in-Publication Data
The Britannica guide to sound and light / edited by Erik Gregersen.
p. cm. — (Physics explained)
“In association with Britannica Educational Publishing, Rosen Educational Services.”
Includes bibliographical references and index.
ISBN 978-1-61530-374-8 (eBook)
1. Sound—Popular works. 2. Light—Popular works. I. Gregersen, Erik. II. Title: Guide
to sound and light. III. Title: Sound and light.
QC225.3.G85 2011
534—dc22
2010013444
On the cover, p. iii: This graphic shows sound waves displayed on an oscilloscope. © www.
istockphoto.com/Clearview images
On page x: Prisms are able to break up white light into its component colors. Shutterstock.com
On page xviii: This graphic shows sound waves displayed on an oscilloscope. Shutterstock.com
On pages 1, 57, 69, 81, 147, 199, 223, 287, 332, 334, 336, 340: Shown here are sound waves
represented on the screen of a device that measures the output of sound. Shutterstock.com
CONTENTS 11
Introduction x
Chapter 1: Sound 1
Plane Waves 2
Wavelength, Period, and Frequency 3
Amplitude and Intensity 4
The Decibel Scale 6
The Speed of Sound 7
Circular and Spherical Waves 11
Attenuation 13
Diffraction 15 31
Refraction 17
Ref ection 19
Impedance 20
Interference 23
The Doppler Effect 25
Sonic Booms 26
Standing Waves 27
In Stretched Strings 28
In Air Columns 33
In Solid Rods 37 31
In Nonharmonic Systems 38
Steady-State Waves and
Spectral Analysis 41 42
The Sound Spectrograph 42
Generation by Musical
Instruments 43
The Human Voice 45
Noise 46
Hearing 47
Dynamic Range of the Ear 47
The Ear as Spectrum Analyzer 50
Binaural Perception 52
Environmental Noise 53
Chapter 2: Acoustics 57
Early Experimentation 57
Modern Advances 60
Amplifying, Recording, and
Reproducing 63
Architectural Acoustics 63
Reverberation Time 64
Acoustic Criteria 65
Acoustic Problems 67
Chapter 3: Beyond Human Hearing 69 89
Ultrasonics 69
Transducers 70
Applications in Research 71 95
Ranging and Navigating 72
The Doppler Effect 73
Materials Testing 73
High-Intensity Applications 74
Chemical and Electrical Uses 75
Medical Applications 75
Infrasonics 78
Chapter 4: Light 81
Theories of Light Through History 83
Ray Theories in the Ancient World 83
Early Particle and Wave Theories 84
102
Geometrical Optics: Light as Rays 87
Light Rays 87
Ref ection and Refraction 89
Total Internal Ref ection 93
Dispersion 94
Light as a Wave 97
Characteristics of Waves 98
Interference 100
Diffraction 106
Diffraction Effects 108
The Doppler Effect 112
Light as Electromagnetic Radiation 113
Electric and Magnetic Fields 113
Maxwell’s Equations 115
Electromagnetic Waves and the
Electromagnetic Spectrum 115
The Speed of Light 119
Polarization 124
Energy Transport 130
Quantum Theory of Light 135
111
Blackbody Radiation 136
Photons 137
Quantum Mechanics 139
Emission and Absorption
Processes 143
Quantum Electrodynamics 145
Chapter 5: Electromagnetic
Radiation 147
General Considerations 147
Occurrence and Importance 148
The Electromagnetic Spectrum 149
Generation of Electromagnetic 118
Radiation 151
Properties and Behaviour 159
Cosmic Background
Electromagnetic Radiation 165
Effect of Gravitation 166
The Greenhouse Effect of the
Atmosphere 166
Forms of Electromagnetic Radiation 167
Radio Waves 168
Microwaves 173
Infrared Radiation 175
170
Visible Radiation 178
Ultraviolet Radiation 181
X-rays 183 204
Gamma Rays 195
Chapter 6: Lasers 199
History 199
Fundamental Principles 202
Energy Levels and Stimulated
Emissions 203
Laser Elements 206
Laser Beam Characteristics 208
Types of Lasers 211
Laser Applications 212
246
Transmission and Processing of
Information 213
Precise Delivery of Energy 214
Alignment, Measurement, and
Imaging 217
Chapter 7: Optics 223
Geometrical Optics 223
The Optical Image 224
Historical Background 224
Ray-Tracing Methods 229
Paraxial, or First-Order, Imagery 234
Optical Systems 241
Lens Aberrations 251
Image Brightness 258
Optics and Information Theory 263
General Observations 263
Image Formation 267
Partially Coherent Light 269
Optical Processing 273
Holography 280
Nonlinear Optics 286 255
Chapter 8: Biographies 287
Sir George Biddell Airy 287
Erasmus Bartholin 288
Nikolay G. Basov 289
Sir David Brewster 290
Arthur Holly Compton 291
Christian Doppler 293
Armand-Hippolyte-Louis Fizeau 293
Harvey Fletcher 295
Jean Foucault 296
Augustin-Jean Fresnel 296 294
Dennis Gabor 298
Hermann von Helmholtz 299
Christiaan Huygens 302
Edwin Herbert Land 307
Hans Lippershey 309
Theodore H. Maiman 309
Étienne-Louis Malus 310
A.A. Michelson 312
Sir Isaac Newton 315
Aleksandr Mikhaylovich Prokhorov 319
John William Strutt,
3rd Lord Rayleigh 320
Ole Rømer 324 303
Wilhelm Röntgen 326
Arthur L. Schawlow 328
Wilebrord van Roijen Snel 329 327
Charles Townes 329
Thomas Young 330
Conclusion 332
Glossary 334
Bibliography 336
Index 340