136 lines
5.3 KiB
HTML
136 lines
5.3 KiB
HTML
<!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html;
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charset=windows-1252">
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<meta name="GENERATOR" content="Mozilla/4.7 [en] (X11; U; OSF1 V4.0
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alpha) [Netscape]">
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<meta name="Author" content="C. L. Davis">
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<title>Magnetism - Introduction - Physics 299</title>
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<meta content="C. L. Davis" name="author">
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</head>
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<body style="color: rgb(0, 0, 0); background-color: rgb(255, 255,
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255);" alink="#ff0000" link="#0000ee" vlink="#551a8b">
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<center>
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<h1> <img src="ULPhys1.gif" align="texttop" height="50"
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width="189"></h1>
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</center>
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<center>
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<h1>Introduction to Magnetism <br>
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</h1>
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</center>
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<center><img src="celticbar.gif" height="22" width="576"><br>
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<br>
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<font color="#ff0000"><i>
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<meta http-equiv="content-type" content="text/html;
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charset=windows-1252">
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</i></font><font color="#ff0000"><i>
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<meta http-equiv="content-type" content="text/html;
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charset=windows-1252">
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</i></font>
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<div class="copy-paste-block"><font color="#ff0000"><i><span
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class="bqQuoteLink">"</span></i></font><font
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color="#ff0000"><i><span class="bqQuoteLink">Physics Is
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Imagination In A Straight Jacket</span></i><span></span>"</font><br>
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</div>
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<font color="#ff0000"><i> </i><font color="#000000">John Moffat</font></font><br>
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</center>
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<img src="netbar.gif" align="middle" height="40" width="100%"> <br>
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<ul>
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</ul>
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<div align="center"><img alt="fig1" src="mag_intro_fig1.jpg"
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height="243" width="325"></div>
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<ul>
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<br>
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<li>As we will see shortly, Electricity and Magnetism are
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different aspects of the same basic physical phenomenon - hence
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the description <a
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href="http://www.britannica.com/EBchecked/topic/183324/electromagnetism">Electromagnetism.</a> </li>
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</ul>
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<ul>
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<li>However, initially it is convenient to treat magnetism in a
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separate, but similar, manner to electricity. In other
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words we will define, magnetic forces, magnetic fields and
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magnetic dipoles exactly as we did the electric variables.</li>
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</ul>
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<ul>
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<li>After this initial description we will develop the
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relationship between magnetism and electricity through Faraday's
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Law of Induction and the Displacement Current, leading finally
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to a complete description of (classical) electromagnetism in the
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form of <a href="http://www.maxwells-equations.com/">Maxwell's
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equations</a>.</li>
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</ul>
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<ul>
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<li>So our starting point in describing magnetism will be the
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assumption of the existence of a magnetic field, <b>B</b>, the
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origin of which will be described later.</li>
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</ul>
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<ul>
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<li><img alt="fig3" src="mag_intro_fig3.jpg" align="right"
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height="193" width="257">Exactly as for the electric field <b>E</b>,
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we will assume that the <b>B</b> field can be represented by
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field lines where,</li>
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</ul>
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<ul>
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<ul>
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<li>the tangent to a field line gives the direction of <b>B</b>
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at that point and</li>
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</ul>
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</ul>
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<ul>
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<ul>
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<li>the number of field lines per unit cross sectional area is
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proportional to the strength of <b>B</b>.</li>
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</ul>
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</ul>
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<ul>
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<li><img alt="exclamation" src="exclamation-icon.gif" height="30"
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width="31"> It is important to realize immediately that unlike
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electric field lines, magnetic field lines <u><i><b>DO NOT</b></i></u>
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represent the direction of the force acting on a charged
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particle.</li>
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</ul>
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<blockquote><img alt="exclamation" src="exclamation-icon.gif"
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height="30" width="31"> The magnetic phenomenon most
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familiar to most people is that of permanent magnetism -
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refrigerator magnets etc. As it happens, permanent magnetism
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is not a simple topic to explain. In fact a complete
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description requires a detailed knowledge of the quantum behavior
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of materials. For this reason we will barely mention
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permanent magnets in this course. <br>
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<br>
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<div align="center"><img alt="fig2" src="mag_intro_fig2.jpg"
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height="202" width="300"><br>
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</div>
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</blockquote>
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<ul>
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</ul>
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<img src="netbar.gif" height="40" width="100%">
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<center>
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<p style="color: rgb(255, 0, 0); font-style: italic;"
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class="MsoNormal">
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<meta http-equiv="content-type" content="text/html;
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charset=windows-1252">
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</p>
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<font color="#ff0000"><i>
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<meta http-equiv="content-type" content="text/html;
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charset=windows-1252">
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Q: What is the name of the first electricity detective?<br>
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A: Sherlock Ohms </i></font><br>
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<br>
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<img src="celticbar.gif" height="22" width="576"> <br>
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<p><i>Dr. C. L. Davis</i> <br>
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<i>Physics Department</i> <br>
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<i>University of Louisville</i> <br>
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<i>email</i>: <a href="mailto:c.l.davis@louisville.edu">c.l.davis@louisville.edu</a>
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<br>
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</p>
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<p><img src="header-index.gif" height="51" width="92"> </p>
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</center>
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<p><br>
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</p>
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</body>
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</html>
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