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Demystifying Electromagnetic Equations: A Complete Explanation of EM Unit Systems and Equation Transformations
Author(s): Douglas L. Cohen
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Book Description

In classical Newtonian mechanics, equations and formulas never change form. The same cannot be said about equations and formulas of electromagnetic theory, which often change form when converted from one system of units to another. Douglas Cohen provides exactly what the technical professional needs: a thorough explanation of how to convert electromagnetic equations from one system of units to another.


Book Details

Date Published: 17 September 2001
Pages: 344
ISBN: 9780819442345
Volume: PM106

Table of Contents
SHOW Table of Contents | HIDE Table of Contents
Preface / vii
1 Outline of Non-Electromagnetic Systems of Units /1
1.1 The basic idea of a unit / 2
1.2 Fundamental and derived units / 4
1.3 Analysis of equations and formulas / 9
1.4 Dimensionless parameters / 11
1.5 The cgs and mks mechanical systems of units / 14
1.6 The U and N operators / 17
1.7 Temperatureunits / 23
1.8 Dimensionlessunits / 24
1.9 Removal of the universal gas constant from the ideal gas law / 29
1.10 Removal of the speed of light from relativistic equations / 37
1.11 Invariant units, connecting units, and addition of extra dimensions / 50
1.12 Simultaneous removal of h, c, and k / 56
References / 64
2 Units Associated with Nineteenth-Century Electromagnetic Theory / 65
2.1 Electric fields, magnetic fields, and Coulomb's law / 66
2.2 Combined systems of electric and magnetic units / 70
2.3 The esu and emu systems of units / 75
2.4 The D and B fields / 86
2.5 The electric and magnetic potentials / 89
2.6 The system of practical units / 91
2.7 The "ab-" and"stat-" prefixes / 96
2.8 The esuq and emuq systems of units / 104
2.9 The esuq and emuq connection with the esu and emu systems of units / 116
2.10 Direct conversion between the esu and emu systems of units / 125
2.11 The B and H fields at the start of the twentieth century / 128
2.12 Electromagnetic concepts used to analyze bulk matter / 133
Appendix 2.A: Magnetic-field measurement in the early nineteenth century / 136
Appendix 2.B: Dimensionless vector derivatives / 139
3 Units Associated with Twentieth-Century Electromagnetic Theory / 149
3.1 Maxwell's equations / 150
3.2 The Gaussian system of units / 151
3.3 Rationalization and the Heaviside-Lorentz system / 166
3.4 Gaussian and Heaviside-Lorentz systems with c = 1 and h = c =1 / 173
3.5 Equivalence of the esu, emu, and Gaussian systems when c = 1 / 180
3.6 Rationalized and unrationalized mks systems / 183
3.7 Conversion of equations to and from the unrationalized mks system / 190
3.8 Conversion of equations to and from the rationalized mks system / 204
3.9 Evaluation of the rationalized mks system / 223
References / 224
4 Two Standard Shortcuts Used to Transform Electromagnetic Equations / 225
4.1 The free-parameter method / 225
4.2 Basic equations using the free parameters k0, um, e and pi/ 236
4.3 Understanding the substitution tables / 274
4.4 Using the substitution tables / 278
4.5 Problems with the free-parameter method and substitution tables / 291
Appendix. Substitution tables / 292
References / 323
Bibliography / 325
Index / 329

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