109 lines
4.2 KiB
HTML
109 lines
4.2 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html;
|
||
|
|
charset=windows-1252">
|
||
|
|
<meta name="GENERATOR" content="Mozilla/4.7 [en] (X11; U; OSF1 V4.0
|
||
|
|
alpha) [Netscape]">
|
||
|
|
<meta name="Author" content="C. L. Davis">
|
||
|
|
<title>Electricty - Electric Potential Energy - Physics 299</title>
|
||
|
|
</head>
|
||
|
|
<body style="color: rgb(0, 0, 0); background-color: rgb(255, 255,
|
||
|
|
255);" alink="#ff0000" link="#0000ee" vlink="#551a8b">
|
||
|
|
<center><img src="ULPhys1.gif" align="texttop" height="50"
|
||
|
|
width="189"></center>
|
||
|
|
<center>
|
||
|
|
<h1>Electric Potential Energy<br>
|
||
|
|
</h1>
|
||
|
|
</center>
|
||
|
|
<center><img src="celticbar.gif" height="22" width="576"><br>
|
||
|
|
<br>
|
||
|
|
<font color="#ff0000"><i>"Atomic power will make electricity too
|
||
|
|
cheap to meter</i>"</font><br>
|
||
|
|
Glenn Seaborg<br>
|
||
|
|
</center>
|
||
|
|
<img src="netbar.gif" align="middle" height="40" width="100%">
|
||
|
|
<br>
|
||
|
|
<ul>
|
||
|
|
<li>It is important to realize that electric potential (potential
|
||
|
|
difference - measured in Volts) is not the same thing as
|
||
|
|
electric potential energy (measured in Joules). We already
|
||
|
|
know how to calculate the pd dues to a system of charges,</li>
|
||
|
|
</ul>
|
||
|
|
<p align="center"><img style="width: 519px; height: 75px;"
|
||
|
|
alt="eqn2" src="elec_potential_eqn2.jpg" height="75" width="519"></p>
|
||
|
|
<blockquote>
|
||
|
|
<p align="left">or for a point charge a distance r<sub>A</sub>
|
||
|
|
from the charge<br>
|
||
|
|
</p>
|
||
|
|
<p align="center"> <img style="width: 177px; height: 60px;"
|
||
|
|
alt="eqn6" src="elec_potential_eqn6.jpg" height="60"
|
||
|
|
width="177"><br>
|
||
|
|
</p>
|
||
|
|
</blockquote>
|
||
|
|
<ul>
|
||
|
|
<li>What about the Potential Energy, PE ?</li>
|
||
|
|
</ul>
|
||
|
|
<blockquote>
|
||
|
|
<p><img alt="elec pot energy fig1" src="elec_potenergy_fig1.gif"
|
||
|
|
align="right" height="191" width="239">Imagine two charges Q
|
||
|
|
and q , with Q at rest. Now gradually bring q<sub> </sub>from
|
||
|
|
|
||
|
|
|
||
|
|
infinity towards<sub> </sub>Q to point P. Then the work
|
||
|
|
done by an external agent in performing this task must be equal
|
||
|
|
to the negative of the work done by the electric field due to Q,<br>
|
||
|
|
</p>
|
||
|
|
<p align="center"><img alt="elec pot energy eqn1"
|
||
|
|
src="elec_potenergy_eqn1.jpg" height="54" width="314"><br>
|
||
|
|
</p>
|
||
|
|
</blockquote>
|
||
|
|
<blockquote>
|
||
|
|
<p align="left">This work is stored in the two charge system as
|
||
|
|
Potential Energy, U<sub>E</sub> ,<br>
|
||
|
|
</p>
|
||
|
|
<div align="center"><img alt="elec pot energy eqn2"
|
||
|
|
src="elec_potenergy_eqn2.jpg" height="54" width="101"><br>
|
||
|
|
<br>
|
||
|
|
<div align="left">For systems of more than 2 charges we must
|
||
|
|
consider all possible pairings to determine the total
|
||
|
|
potential energy.<br>
|
||
|
|
<br>
|
||
|
|
<img alt="exclamation" src="exclamation-icon.gif" height="30"
|
||
|
|
width="31"> For U > 0 energy must be provided to
|
||
|
|
create the system<br>
|
||
|
|
For U < 0 energy must be
|
||
|
|
provided to break up the system (initially this system is
|
||
|
|
"bound") <br>
|
||
|
|
<br>
|
||
|
|
<img alt="exclamation" src="exclamation-icon.gif" height="30"
|
||
|
|
width="31"> Don't forget - Change in PE = work
|
||
|
|
needed to accomplish the change.<br>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</blockquote>
|
||
|
|
<p> <img src="netbar.gif" height="40" width="100%"> </p>
|
||
|
|
<center>
|
||
|
|
<p class="MsoNormal"><span style="color: rgb(255, 0, 0);
|
||
|
|
font-style: italic;">
|
||
|
|
<meta http-equiv="content-type" content="text/html;
|
||
|
|
charset=windows-1252">
|
||
|
|
Do you realize if it weren't for Edison we'd be watching TV by
|
||
|
|
candlelight?</span><br>
|
||
|
|
Al Boliska<br>
|
||
|
|
</p>
|
||
|
|
<img src="celticbar.gif" height="22" width="576"> <br>
|
||
|
|
|
||
|
|
<p><i>Dr. C. L. Davis</i> <br>
|
||
|
|
<i>Physics Department</i> <br>
|
||
|
|
<i>University of Louisville</i> <br>
|
||
|
|
<i>email</i>: <a href="mailto:c.l.davis@louisville.edu">c.l.davis@louisville.edu</a>
|
||
|
|
<br>
|
||
|
|
</p>
|
||
|
|
<p><img src="header-index.gif" height="51" width="92"> </p>
|
||
|
|
</center>
|
||
|
|
<p><br>
|
||
|
|
</p>
|
||
|
|
</body>
|
||
|
|
</html>
|