109 lines
4.2 KiB
HTML
109 lines
4.2 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>Electricty - Electric Potential Energy - Physics 299</title>
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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><img src="ULPhys1.gif" align="texttop" height="50"
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width="189"></center>
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<center>
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<h1>Electric Potential Energy<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>"Atomic power will make electricity too
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cheap to meter</i>"</font><br>
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Glenn Seaborg<br>
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</center>
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<img src="netbar.gif" align="middle" height="40" width="100%">
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<br>
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<ul>
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<li>It is important to realize that electric potential (potential
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difference - measured in Volts) is not the same thing as
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electric potential energy (measured in Joules). We already
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know how to calculate the pd dues to a system of charges,</li>
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</ul>
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<p align="center"><img style="width: 519px; height: 75px;"
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alt="eqn2" src="elec_potential_eqn2.jpg" height="75" width="519"></p>
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<blockquote>
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<p align="left">or for a point charge a distance r<sub>A</sub>
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from the charge<br>
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</p>
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<p align="center"> <img style="width: 177px; height: 60px;"
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alt="eqn6" src="elec_potential_eqn6.jpg" height="60"
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width="177"><br>
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</p>
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</blockquote>
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<ul>
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<li>What about the Potential Energy, PE ?</li>
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</ul>
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<blockquote>
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<p><img alt="elec pot energy fig1" src="elec_potenergy_fig1.gif"
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align="right" height="191" width="239">Imagine two charges Q
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and q , with Q at rest. Now gradually bring q<sub> </sub>from
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infinity towards<sub> </sub>Q to point P. Then the work
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done by an external agent in performing this task must be equal
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to the negative of the work done by the electric field due to Q,<br>
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</p>
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<p align="center"><img alt="elec pot energy eqn1"
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src="elec_potenergy_eqn1.jpg" height="54" width="314"><br>
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</p>
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</blockquote>
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<blockquote>
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<p align="left">This work is stored in the two charge system as
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Potential Energy, U<sub>E</sub> ,<br>
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</p>
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<div align="center"><img alt="elec pot energy eqn2"
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src="elec_potenergy_eqn2.jpg" height="54" width="101"><br>
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<br>
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<div align="left">For systems of more than 2 charges we must
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consider all possible pairings to determine the total
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potential energy.<br>
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<br>
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<img alt="exclamation" src="exclamation-icon.gif" height="30"
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width="31"> For U > 0 energy must be provided to
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create the system<br>
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For U < 0 energy must be
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provided to break up the system (initially this system is
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"bound") <br>
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<br>
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<img alt="exclamation" src="exclamation-icon.gif" height="30"
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width="31"> Don't forget - Change in PE = work
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needed to accomplish the change.<br>
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</div>
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</div>
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</blockquote>
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<p> <img src="netbar.gif" height="40" width="100%"> </p>
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<center>
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<p class="MsoNormal"><span style="color: rgb(255, 0, 0);
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font-style: italic;">
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<meta http-equiv="content-type" content="text/html;
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charset=windows-1252">
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Do you realize if it weren't for Edison we'd be watching TV by
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candlelight?</span><br>
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Al Boliska<br>
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</p>
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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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