Article View: sci.physics
Article #7656Re: capacitors
From: Ian Phillipps
Date: Fri, 27 May 1988 13:55
Date: Fri, 27 May 1988 13:55
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1551 bytes
From article <271@snjsn1.SJ.ATE.SLB.COM>, by chuckc@trojan (Charles Crapuchettes): > In article <2992@phoenix.Princeton.EDU> tycchow@phoenix.Princeton.EDU (Timothy Yi-chung Chow) writes: >>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? >>... However, suppose we idealize the problem and assume zero resistance. >> Surely energy is still lost somehow. How do we explain this? Energy IS lost - to electromagnetic radiation. Antenna designers use the idea of "radiation impedance" to allow for this - about 75 ohm for a half-wavelength and (I think) proportional for shorter bits of wire. So, even in the "ideal" case, energy is dissipated. (Not lost, of course!) -- UUCP: ...!ukc!camcon!igp | Cambridge Consultants Ltd | Ian Phillipps or: igp@camcon.uucp | Science Park, Milton Road |----------------- Phone: +44 223 358855 | Cambridge CB4 4DW, England |
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!lll-tis!lll-winken!uunet!mcvax!ukc!stl!stc!idec!camcon!igp From: igp@camcon.uucp (Ian Phillipps) Newsgroups: sci.physics,sci.electronics Subject: Re: capacitors Message-ID: <1516@titan.camcon.uucp> Date: 27 May 88 13:55:45 GMT References: <271@snjsn1.SJ.ATE.SLB.COM> Organization: Cambridge Consultants Ltd., Cambridge, UK Lines: 20