Magic capacitors!
in [Design]
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From: George Jefferson on 21 Jul 2010 08:54 Suppose you have two capacitors connected as --*-- | | C1 C2 | | ----- where * is a switch. What is the total energy before and after the switch is closed(in general). If you want to make it easier assume C2 is initially discharged. Is the energy before and after the same? If not explain why and why it is not a violation of the conservation of energy law.
From: Michael Förtsch on 21 Jul 2010 09:43 George Jefferson wrote: > [rather old riddle] > > Is the energy before and after the same? If not explain why and why it > is not a violation of the conservation of energy law. The total electrical energy after the charge has been transfered is 50% of the electrical energy that was stored in C1. The residual 50% had been handed to the government as a charge transfer tax.
From: John Larkin on 21 Jul 2010 11:07 On Wed, 21 Jul 2010 07:54:03 -0500, "George Jefferson" <phreon111(a)gmail.com> wrote: >Suppose you have two capacitors connected as > >--*-- >| | >C1 C2 >| | >----- > >where * is a switch. > >What is the total energy before and after the switch is closed(in general). Energy is conserved, so it's the same, if you account for all the manifestations of energy. > >If you want to make it easier assume C2 is initially discharged. > >Is the energy before and after the same? If not explain why and why it is >not a violation of the conservation of energy law. Ancient puzzle, done to death on the web and, lately, in this ng. John
From: George Jefferson on 21 Jul 2010 12:19 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:s43e46la1p1vt11527eg3ptl9ulm44dfrj(a)4ax.com... > On Wed, 21 Jul 2010 07:54:03 -0500, "George Jefferson" > <phreon111(a)gmail.com> wrote: > >>Suppose you have two capacitors connected as >> >>--*-- >>| | >>C1 C2 >>| | >>----- >> >>where * is a switch. >> >>What is the total energy before and after the switch is closed(in >>general). > > Energy is conserved, so it's the same, if you account for all the > manifestations of energy. > You didn't answer the question. I assume this because you don't know.
From: John Larkin on 21 Jul 2010 12:24
On Wed, 21 Jul 2010 11:19:31 -0500, "George Jefferson" <phreon111(a)gmail.com> wrote: > > >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:s43e46la1p1vt11527eg3ptl9ulm44dfrj(a)4ax.com... >> On Wed, 21 Jul 2010 07:54:03 -0500, "George Jefferson" >> <phreon111(a)gmail.com> wrote: >> >>>Suppose you have two capacitors connected as >>> >>>--*-- >>>| | >>>C1 C2 >>>| | >>>----- >>> >>>where * is a switch. >>> >>>What is the total energy before and after the switch is closed(in >>>general). >> >> Energy is conserved, so it's the same, if you account for all the >> manifestations of energy. >> > >You didn't answer the question. I assume this because you don't know. > State the question unambiguously and I will. As I said, the puzzle is both ancient and trivial, so probably JT invented it. There are web sites and even academic papers devoted to it. Given all that, how could I not understand it? John |