On Sat, 03 Dec 2011 09:28:17 -0800, John Larkin
wrote:

On Sat, 03 Dec 2011 08:23:23 -0700, Jim Thompson
wrote:

On Sat, 03 Dec 2011 04:24:47 -0600, John Fields
wrote:

On Fri, 02 Dec 2011 11:45:49 -0800, John Larkin
wrote:

On Fri, 02 Dec 2011 07:51:45 -0700, Jim Thompson
wrote:

On Fri, 02 Dec 2011 09:11:00 -0500, JW wrote:

On Fri, 02 Dec 2011 06:23:36 -0600 John Fields
wrote in Message id:
:


BTW, if you swing a magnet past a wire, what's induced in the wire?

Is the wire connected to anything?

Bwahahahahaha! Larkin would opine that there's a voltage end-to-end.
;-)

...Jim Thompson

It's an alternator. A voltage is induced, and the wire/coil has some
impedance.

---
If one were to connect a voltmeter across the otherwise open ends of a
conductor, and that conductor was excited by a varying magnetic field,
the voltmeter would indeed register a varying voltage.


The only way to connect the voltmeter is to use leads. Then you have a
loop. If you keep the leads very close to the wire, as you reduce the
loop area, the voltage goes to zero.



After I posted I realized I'd put my foot in it because, in a way,
that's how semiconductors work... particularly MOS.

Mosfets are magnetic devices?



The underlying cause, however, would be the concentration and dilution
of charge at the ends of the wire.

Indeed.


That concentration and dilution would be caused by the movement of
electrons in the wire, that movement being defined as current.


Yep.

...Jim Thompson


OK: make a 1 meter radius wire ring with a small gap. Push through it
a perpendicular, uniform magnetic field that ramps up at 1 T/second.

What's the voltage across the gap?

More importantly, what's the current in the wire?


JF? JT?
---
JL.

Since it's _you_ who's been taken to task, it behooves you to defend
yourself.

You're very big at telling people what to do, but tiny at doing your
own legwork so, instead of pretending to authority, if you've got a
point to make and you want to make it physically, why not just shut
the **** up, do the work, and report back with findings which
incontrovertibly quash your detractors?

That is, since you proposed the experiment, why don't _you_ make a 1
meter radius wire ring with a small gap, push through it a
perpendicular, uniform magnetic field that ramps up at 1 T/second, and
report back with what happened?

If you ever get to it, instead of just mouthing opinion I'd be
interested in learning how the voltage across the gap changed, and
especially interested in learning how you managed to measure the
current in the unconnected wire.

--
JF