Let's Take A Vote...

--- Cordially, Jim,

All you're up against is Larkin's sophistry, and whether any of us votes as to whether charge is conserved or not is immaterial, since nature rules.

Post what you've got and let the chips fall where they may, there's always Wikipedia which supports your position:

On the other hand, if Larkin's right and energy is conserved but charge isn't, then since charge is a measure of force, unbalanced lost charge might be able to be used for propulsion.

Charge is measured in coulombs. Force is measured in newtons. So how is charge "a measure of force"?

John

Let the John "The Bloviator" Larkin sophistry begin ;-) ...Jim Thompson

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           Only as good as the person behind the wheel.

This is probably simple to someone like Richard Feynman, but if it isn't "conserved," where does it go?

Thanks, Rich [wondering if I should have posted this as The Philosophizer. ;-) ]\

What's "electromotive force?" Its units are "volts," right?

What was the original question?

Thanks, Rich

Now force is measured in volts? Dang, I was just getting used to measuring it in coulombs.

I have no idea. We're waiting for a "mathematical proof" of something, which might even include a statement of the problem. They often start out that way.

John

I define "charge" as total number of electrons and state one neither gains or loses electrons (except via nuclear interactions); they CAN (and will) move around - even "tunnel" from here to there.

Lessee...

*force (vector)F, dimensions : M L T^-2 (derived unit Newton). *charge q, dimensions : Q (derived unit coulomb). Hmmm absolutely no similarity; need a conversion factor that adds the correct dimensions.... Maybe as a wild guess try electric field strength (vector)E, M L T^-2Q^-1 (derived unit volts/meter)?

You have never heard of electrons dropping in the bit bucket? You can tell by way of the oil tracks from Millikan's experiment.

See my previous posting..

r .

ds

Volt =3D joule/coulomb

Does that help?

It depends on the context and your definitions, as already pointed out and which you still refuse to provide. Are you using a definition which says capacitors store charge or not? Is the quantity Q=CV to be regarded as "charge" or not? Is charge "delivered" or does it "flow through"?

*Without* any context, I would have said "charge is conserved". You don't need to spend three weeks proving this, just point to Kirchoff.

But the context of the original thread was all abouit switched capacitors and whether the "capacitors charge" was always conserved when transfered to another. We routinely refer to the quantity Q=CV as the capacitors "charge", it is this quantity which is not conserved, I.e., you can sum them before and after the switching operation and it is different. Not sophistry, just a normal use of terms in a circuit description.

And it is obvious that this was the intended usage, since otherwise the "charge of the capacitor" is always zero!

Basically, our routine use of the word is ambiguous, you can easily "prove someone wrong" by assuming the opposite usage to that intended,

--

John Devereux

Hopefully not too many. But it is difficult to predict the behaviour of electronics engineers - about half of them think Einstein was wrong :(

Just about every physicist on the planet since Ben Franklin.

It was the inconsistency of Ampere's Law with conservation of charge that led Maxwell to formulate his famous equations and show that oscillating fields of electromagnetic radiation travel at a constant speed c in a vacuum.

A idealised physics version of your original capacitor problem but without the switch can be stated as the following problem:

Two identical metal spheres with capacitance C are used. Initially one is uncharged and the other with a charge Q

They are brought together from infinity until they touch.

Describe what happens and how the charge is distributed after they are in electrical contact. You can add an infinite ground plane under the experiment if it makes you feel better about the circuit analogue.

Regards, Martin Brown

=A0 =A0 =A0...Jim Thompson

There is a "switch" in your "idealized" example, and a non-ideal one at that. It's commonly called a "spark gap". They tend to radiate a bit.

Back to square one.

Mark L. Fergerson

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news:2apl46hr8s01os8dv1aipdm19bcf64nec4@4ax.com

=A0 =A0 ...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

In college, we had this experiment where we would rub an inflated balloon to build a static charge on it. Then, drop the balloon into a Faraday cage to measure the charge. (About 200 nanocoulombs, IIRC). If you removed the balloon from the chamber, the charge removed with it. However, if you popped the charged balloon while it was inside the cage, and then removed the balloon's carcass, the charge stayed in the chamber.

So, based on the above, I would have to say this doesn't directly answer your question. But I thought it was an interesting enough experiment to bring up, for those who never conducted it (no pun intended) in college.

-mpm

--
Oh, and the first sentence of the cited Wikipedia article reads: 

"Electric charge is a physical property of matter which causes it
to experience a force when near other electrically charged matter."

 
JF

If you experience a pig, does that make you a pig?

Look at the SI units if you want to determine if things are the same.

Is a pig a Field?

John