Xref: utzoo sci.electronics:6360 sci.physics:8352
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From: vaso@mips.COM (Vaso Bovan)
Newsgroups: sci.electronics,sci.physics
Subject: Re: HV Cap Fun!
Summary: Capacitor Energy Storage
Message-ID: <20772@quacky.mips.COM>
Date: 31 May 89 08:38:31 GMT
References: <4924@m2c.M2C.ORG> <3806@mit-amt>
Reply-To: vaso@mips.COM (Vaso Bovan)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 13
Keywords:capacitor,energy,paradox

A Paradox of Capacitor Energy Storage

I've heard several competing answers to this paradox. None is entirely
satisfactory:

Consider an ideal 2uF (for computational ease) capacitor charged by a 10 volt 
source. Eventually, the energy stored is (1/2)*CV^2=100 joules.

Consider the capacitor to be isolated from the voltage source, and then
directly shorted across an identical (ideal) capacitor. Eventually, the
voltage across each capacitor will be 5V. Now, there are two equally
charged capacitors, each storing (1/2)*CV^2= 25 joules, for a total of
of 50 joules.  What happened to the other 50 joules ?