Xref: utzoo sci.electronics:8000 sci.physics:9843 Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!amdahl!amdcad!diablo!phil From: phil@diablo.amd.com (Phil Ngai) Newsgroups: sci.electronics,sci.physics Subject: Re: A violation of the law of conservation of energy Keywords: paradox Message-ID: <27549@amdcad.AMD.COM> Date: 29 Sep 89 02:11:58 GMT References: <318@massey.ac.nz> Sender: news@amdcad.AMD.COM Reply-To: phil@diablo.AMD.COM (Phil Ngai) Organization: Advanced Micro Devices, Inc. Sunnyvale CA Lines: 18 In article <318@massey.ac.nz> ARaman@massey.ac.nz (A.V. Raman) writes: |By definition then, the energy transferred from V to C is |charge * pressure = 1V * 1C = 1 joule |But what is the energy stored in the capacitor? |It is half C*square(V) = half * 1 * square(1) = half joule. |Where has the remaining half joule gone? |Beats me! Congratulations, you've come up with an example which shows that the circuit model of reality has idealizations which can lead to incorrect answers. Any model of reality will have corners where they are not useful. Part of your job as an engineer is to know when you are getting close to one of those corners and what to do about it. In this case, you have to go to a lower level and use an E&M model. -- Phil Ngai, phil@diablo.amd.com {uunet,decwrl,ucbvax}!amdcad!phil "Should the US send assault rifles to Colombia? How about small arms?"