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Re: mag. force on wire?



Let B, the magnetic field, be into the page.
1) a current consisting only of electrons moving to the right will be
forced by QVxB toward the page bottom, giving a Hall effect voltage is
negative at the page bottom.

2) a current consisting of an unoccupied electron state (a hole - a
positive ion) which "moves" to the left (by means of electrons moving to
the right as they fill a neighboring vacancy) will result in this entire
process being forced to the page bottom, making the page bottom positive
(that's where the ion is).

Bob

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----
From: Leon Leonardo <lleonardo1@YAHOO.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Wednesday, November 03, 1999 12:33 AM
Subject: mag. force on wire?


Greetings,

I'm about ready to cover magnetic forces on a current
carrying wire when I realized how little I understand
what's really happening. Any help would be appreciated
concerning the following:

Just how is it that the force on moving charges
"contained" in a wire is transferred to the wire
itself? I've problems with the two explanations that
seem pretty standard. That is, by collisions (with
what, exactly, and what happens at the boundary?); and
by electrostatic separation of charges (what happens
if both positive and negative charges are equally
responsible for charge flow?)

Another question: HOw can the Hall effect distinguish
hole-flow (P's) from 'N's in a semi-conductor when in
either it is electrons that are actually flowing?



Any thoughts?

:Leon

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