Article View: sci.physics
Article #7655Re: capacitors
From: Leonard Erickson
Date: Wed, 25 May 1988 09:34
Date: Wed, 25 May 1988 09:34
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1938 bytes
In article <2992@phoenix.Princeton.EDU> tycchow@phoenix.Princeton.EDU (Timothy Yi-chung Chow) writes: <The following problem appears in many books on elementary physics, <elementary electromagnetism, and elementary circuit theory: < <Two capacitors, with capacitances C1 and C2 respectively, carry <charges Q1 and Q2 respectively. Find the total energy stored. <Now connect the positive plates and connect the negative plates. <Show that the total energy stored decreases. Where has the <energy gone? < <The energy calculations are trivial. What intrigues me is the <question of the lost energy. The answer usually given is that <a current flows when the capacitors are connected, and this <causes energy to be dissipated as heat. However, suppose we <idealize the problem and assume zero resistance. Surely energy <is still lost somehow. How do we explain this? The only time I came across this problem was in an old physics book dug out of a storeroom when I was in high school. The text explicitly stated that the energy was lost as electromagnetic radiation and gave formulas for calculating the frequency(!). I lost my copies of these and many other interesting formulas when my briefcase was stolen late in my junior year :-( -- Leonard Erickson ...!tektronix!reed!percival!bucket!leonard CIS: [70465,203] "I used to be a hacker. Now I'm a 'microcomputer specialist'. You know... I'd rather be a hacker."
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!tektronix!tekgen!teksce!bucket!leonard From: leonard@bucket.UUCP (Leonard Erickson) Newsgroups: sci.physics,sci.electronics Subject: Re: capacitors Keywords: electromagnetism, capacitors, circuits Message-ID: <898@bucket.UUCP> Date: 25 May 88 09:34:18 GMT References: <2992@phoenix.Princeton.EDU> Reply-To: leonard@bucket.UUCP (Leonard Erickson) Organization: Rick's Home Grown Unix; Portland, OR Lines: 30