Update 2022-02-08 07:07

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Jean-Sébastien
2022-02-08 07:07:41 +01:00
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209 changed files with 1478 additions and 54683 deletions
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@@ -1,7 +1,7 @@
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<head>
<!-- 2022-02-07 Mon 08:02 -->
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<title>Pre-Quantum Electrodynamics</title>
@@ -348,58 +348,12 @@ Table of contents
</li>
<li>
<details>
<summary>
<a href="./ems_es_efo_exp.html#ems_es_efo_exp">Experimental Investigations</a><span class="headline-id">ems.es.efo.exp</span>
</summary>
<ul>
<li>
<a href="#org788e483">Before Coulomb</a>
</li>
<li>
<a href="#org8b037d5">Cavendish's experiment</a>
</li>
<li>
<a href="#org1f82edc">Coulomb</a>
</li>
<li>
<a href="#org359fd13">Current status</a>
</li>
</ul>
</details>
</li>
<li>
<details open="">
<summary class="toc-currentpage">
<li class="toc-currentpage">
<a href="./ems_es_efo_e.html#ems_es_efo_e">Energy in Systems of Point Charges</a><span class="headline-id">ems.es.efo.e</span>
</summary>
<ul>
<li>
<a href="#ems_es_efo_e_p">Work; Pairwise Energy</a>
</li>
<li>
<a href="#ems_es_efo_e_ga">Generic assembly</a>
</li>
<li>
<a href="#ems_es_efo_e_cl">Crystal lattices</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -427,25 +381,8 @@ Table of contents
</li>
<li>
<details>
<summary>
<a href="./ems_es_ef_Gl.html#ems_es_ef_Gl">Gauss's Law: the divergence of \({\bf E}\)</a><span class="headline-id">ems.es.ef.Gl</span>
</summary>
<ul>
<li>
<a href="#ems_es_ef_Gl_fl">Field Lines, Flux and Gauss's Law</a>
</li>
<li>
<a href="#ems_es_ef_Gl_ex">Examples of applications of Gauss's law</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -455,7 +392,7 @@ Table of contents
<details>
<summary>
<a href="./ems_es_ep.html#ems_es_ep">Electrostatic Potential</a><span class="headline-id">ems.es.ep</span>
<a href="./ems_es_ep.html#ems_es_ep">The Electrostatic Potential</a><span class="headline-id">ems.es.ep</span>
</summary>
@@ -492,7 +429,7 @@ Table of contents
<details>
<summary>
<a href="./ems_es_e.html#ems_es_e">Electrostatic Energy</a><span class="headline-id">ems.es.e</span>
<a href="./ems_es_e.html#ems_es_e">Electrostatic Energy from the Potential</a><span class="headline-id">ems.es.e</span>
</summary>
@@ -565,29 +502,8 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./ems_ca_fe_L.html#ems_ca_fe_L">The Laplace Equation</a><span class="headline-id">ems.ca.fe.L</span>
</summary>
<ul>
<li>
<a href="#ems_ca_fe_L_1d">The Laplace Equation in One Dimension</a>
</li>
<li>
<a href="#ems_ca_fe_L_2d">The Laplace Equation in Two Dimensions</a>
</li>
<li>
<a href="#ems_ca_fe_L_3d">The Laplace Equation in Three Dimensions</a>
</li>
</ul>
</details>
</li>
<li>
<a href="./ems_ca_fe_g.html#ems_ca_fe_g">Green's Identities</a><span class="headline-id">ems.ca.fe.g</span>
@@ -871,33 +787,8 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./emsm_esm_di_ld.html#emsm_esm_di_ld">Linear Dielectrics</a><span class="headline-id">emsm.esm.di.ld</span>
</summary>
<ul>
<li>
<a href="#emsm_esm_d_ld_sp">Susceptibility, Permittivity, Dielectric Constant</a>
</li>
<li>
<a href="#emsm_esm_di_ld_bvp">Boundary Value Problems with Linear Dielectrics</a>
</li>
<li>
<a href="#emsm_esm_di_ld_e">Energy in Dielectric Systems</a>
</li>
<li>
<a href="#emsm_esm_di_ld_f">Forces on Dielectrics</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -926,21 +817,8 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./emsm_msm_m_dpf.html#emsm_msm_m_dpf">Diamagnetism, Paramagnetism, Ferromagnetism</a><span class="headline-id">emsm.msm.m.dpf</span>
</summary>
<ul>
<li>
<a href="#org65874b3">Why is Ferromagnetism such an intriguing phenomenon?</a>
</li>
</ul>
</details>
</li>
<li>
<a href="./emsm_msm_m_fdi.html#emsm_msm_m_fdi">Torques and Forces on Magnetic Dipoles</a><span class="headline-id">emsm.msm.m.fdi</span>
@@ -989,25 +867,8 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./emsm_msm_H_A.html#emsm_msm_H_A">Ampère's Law in Magnetized Materials</a><span class="headline-id">emsm.msm.H.A</span>
</summary>
<ul>
<li>
<a href="#emsm_msm_H_A_dp">A Deceptive Parallel</a>
</li>
<li>
<a href="#emsm_msm_H_A_elm">Energy in Linear Media</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -1599,37 +1460,8 @@ Table of contents
</li>
<li>
<details>
<summary>
<a href="./c_m_dc_d2.html#c_m_dc_d2">Second Derivatives</a><span class="headline-id">c.m.dc.d2</span>
</summary>
<ul>
<li>
<a href="#orge025182">Divergence of gradient</a>
</li>
<li>
<a href="#orgacb930d">Curl of a gradient</a>
</li>
<li>
<a href="#org6caee98">Gradient of the divergence</a>
</li>
<li>
<a href="#orgb5da747">Divergence of a curl</a>
</li>
<li>
<a href="#orgebcbadc">Curl of curl</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -1645,29 +1477,8 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./c_m_ic_lsv.html#c_m_ic_lsv">Line, Surface and Volume Integrals</a><span class="headline-id">c.m.ic.lsv</span>
</summary>
<ul>
<li>
<a href="#org638a76f">Line Integrals</a>
</li>
<li>
<a href="#orgd8e925a">Surface Integrals</a>
</li>
<li>
<a href="#org5c24b4a">Volume Integrals</a>
</li>
</ul>
</details>
</li>
<li>
<a href="./c_m_ic_ftc.html#c_m_ic_ftc">The Fundamental Theorem of Calculus</a><span class="headline-id">c.m.ic.ftc</span>
@@ -1703,62 +1514,12 @@ Table of contents
</summary>
<ul>
<li>
<details>
<summary>
<a href="./c_m_cs_sph.html#c_m_cs_sph">Spherical Coordinates</a><span class="headline-id">c.m.cs.sph</span>
</summary>
<ul>
<li>
<a href="#c_m_cs_sph_grad">Gradient</a>
</li>
<li>
<a href="#c_m_cs_sph_div">Divergence</a>
</li>
<li>
<a href="#c_m_cs_sph_curl">Curl</a>
</li>
<li>
<a href="#c_m_cs_sph_lap">Laplacian</a>
</li>
</ul>
</details>
</li>
<li>
<details>
<summary>
<a href="./c_m_cs_cyl.html#c_m_cs_cyl">Cylindrical Coordinates</a><span class="headline-id">c.m.cs.cyl</span>
</summary>
<ul>
<li>
<a href="#c_m_cs_cyl_grad">Gradient</a>
</li>
<li>
<a href="#c_m_cs_cyl_div">Divergence</a>
</li>
<li>
<a href="#c_m_cs_cyl_curl">Curl</a>
</li>
<li>
<a href="#c_m_cs_cyl_lap">Laplacian</a>
</li>
</ul>
</details>
</li>
<li>
<a href="./c_m_cs_hyp.html#c_m_cs_hyp">Hyperbolic Coordinates</a><span class="headline-id">c.m.cs.hyp</span>
@@ -1807,25 +1568,8 @@ Table of contents
</li>
<li>
<details>
<summary>
<a href="./c_m_vf_pot.html#c_m_vf_pot">Potentials</a><span class="headline-id">c.m.vf.pot</span>
</summary>
<ul>
<li>
<a href="#c_m_vf_pot_irrot">Theorem 1: Curl-less (irrotational) fields</a>
</li>
<li>
<a href="#c_m_vf_pot_solen">Theorem 2: Divergence-less (solenoidal) fields</a>
</li>
</ul>
</details>
</li>
</ul>
@@ -1868,20 +1612,26 @@ Table of contents
</ul>
</details>
</nav>
<ul class="navigation-links"><li>Prev:&nbsp;<a href="org359fd13.html">Current status&emsp;<small>[org359fd13]</small></a></li><li>Next:&nbsp;<a href="ems_es_efo_e_p.html">Work; Pairwise Energy&emsp;<small>[ems.es.efo.e.p]</small></a></li><li>Up:&nbsp;<a href="ems_es_efo.html">Electric Force and Energy&emsp;<small>[ems.es.efo]</small></a></li></ul><div id="outline-container-ems_es_efo_e" class="outline-5">
<ul class="navigation-links"><li>Prev:&nbsp;<a href="ems_es_efo_exp.html">Experimental Investigations&emsp;<small>[ems.es.efo.exp]</small></a></li><li>Next:&nbsp;<a href="ems_es_ef.html">Electrostatic Fields&emsp;<small>[ems.es.ef]</small></a></li><li>Up:&nbsp;<a href="ems_es_efo.html">Electric Force and Energy&emsp;<small>[ems.es.efo]</small></a></li></ul><div id="outline-container-ems_es_efo_e" class="outline-5">
<h5 id="ems_es_efo_e">Energy in Systems of Point Charges<a class="headline-permalink" href="./ems_es_efo_e.html#ems_es_efo_e"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
<path d="M6.354 5.5H4a3 3 0 0 0 0 6h3a3 3 0 0 0 2.83-4H9c-.086 0-.17.01-.25.031A2 2 0 0 1 7 10.5H4a2 2 0 1 1 0-4h1.535c.218-.376.495-.714.82-1z"/>
<path d="M9 5.5a3 3 0 0 0-2.83 4h1.098A2 2 0 0 1 9 6.5h3a2 2 0 1 1 0 4h-1.535a4.02 4.02 0 0 1-.82 1H12a3 3 0 1 0 0-6H9z"/>
</svg></a><span class="headline-id">ems.es.efo.e</span></h5>
<div class="outline-text-5" id="text-ems_es_efo_e">
<ul class="org-ul altsecnrs">
<li>FLS II 8</li>
<li>Gr 2.4.2</li>
<li>PM 1.5</li>
</ul>
</div>
<div id="outline-container-ems_es_efo_e_p" class="outline-6">
<h6 id="ems_es_efo_e_p"><a href="#ems_es_efo_e_p">Work; Pairwise Energy</a></h6>
<div class="outline-text-6" id="text-ems_es_efo_e_p">
<p>
Consider some distribution of charge which produces an electric field.
How much work is needed to carry a small test charge \(q_t\) from one place to another, <i>i.e.</i> from point \({\bf a}\) to point \({\bf b}\) ?
Consider some distribution of charge which is held statically in place.
How much work is needed to adiabatically move a small test charge \(q_t\) from one
position to another, <i>i.e.</i> from point \({\bf a}\) to point \({\bf b}\) ?
</p>
<p>
@@ -1911,8 +1661,8 @@ For the path, the 'angular' part is not contributing (see drawings in
FLS II 4-3). The integral is thus purely radial,
</p>
<div class="eqlabel" id="orgdf595d6">
<div class="alteqlabels" id="org6cae870">
<div class="eqlabel" id="org70d5df1">
<div class="alteqlabels" id="org206a74a">
<ul class="org-ul">
<li>Gr (2.18)</li>
</ul>
@@ -1929,14 +1679,14 @@ FLS II 4-3). The integral is thus purely radial,
<p>
As should be clear by now, this result does not depend on the path
(if it did, we'd have a <i>perpetuum mobile</i> when going from \({\bf r}_a\)
to \({\bf r}_a\) one way, and coming back another).
to \({\bf r}_b\) one way, and coming back another).
</p>
<p>
When thinking about the energy of this pair of charges, we think
of starting from an initial configuration where the charges are infinitely
distance (which we associate to zero energy), and thus set \({\bf r}_a = \infty\).
We can thus write
For a pair of charges, the energy is thus
</p>
<p>
@@ -1944,17 +1694,10 @@ We can thus write
W = \frac{1}{4\pi \varepsilon_0} \frac{q_t q_s}{|{\bf r}_t - {\bf r}_s|}
\]
</p>
<div class="example div" id="orgfdafc11">
<p>
<b>Example</b>: fission
</p>
</div>
</div>
</div>
<div id="outline-container-ems_es_efo_e_ga" class="outline-6">
<h6 id="ems_es_efo_e_ga"><a href="#ems_es_efo_e_ga">Generic assembly</a></h6>
<div class="outline-text-6" id="text-ems_es_efo_e_ga">
@@ -1982,9 +1725,10 @@ where in the second equality we have symmetrized the sums for convenience.
<div id="outline-container-ems_es_efo_e_cl" class="outline-6">
<h6 id="ems_es_efo_e_cl"><a href="#ems_es_efo_e_cl">Crystal lattices</a></h6>
<div class="outline-text-6" id="text-ems_es_efo_e_cl">
<p>
PM3:1.6
</p>
<ul class="org-ul altsecnrs">
<li>FLS II 8-4</li>
<li>PM 1.6</li>
</ul>
</div>
</div>
</div>
@@ -1992,7 +1736,7 @@ PM3:1.6
<hr><div id="postamble" class="status">
<p class="author">Author: Jean-Sébastien Caux</p>
<p class="date">Created: 2022-02-07 Mon 08:02</p>
<p class="date">Created: 2022-02-08 Tue 06:55</p>
<p class="validation"><a href="https://validator.w3.org/check?uri=referer">Validate</a></p>
</div>