Xref: utzoo sci.physics:3506 sci.electronics:3022
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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

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!)
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