simple magnets question

[William Beaty <billb@ESKIMO.COM>]

On Fri, 25 Jun 1999, Leigh Palmer wrote:

> I don't remember when I missed it, but someone suggested that a disk
> magnet spinning on its axis of symmetry might have a radial electric
> field.

A radial electric field across the surface of its flat face, yes.  The
"Faraday's Disk" experiment seems to prove that this is a real, measurable
field.

The thread "simple magnets question" started as below:

------
Date: Wed, 23 Jun 1999 12:05:17 -0700 (PDT)
From: William Beaty <billb@eskimo.com>
To: Forum for Physics Educators <PHYS-L@LISTS.NAU.EDU>
Subject: simple magnets question


I was recently reminded of something that's been bugging me.  When an
electron moves at right angles to a uniform b-field in a vacuum, it
follows a circular path.  What happens if we turn this situation
inside-out? Suppose we place an electron in the field of a thin
disk-shaped permanent magnet which has poles on the opposite faces of the
disk, and then we briefly rotate the disk on axis.  Assume that everything
is stationary at the beginning, then reach out and give the disk-magnet a
twist.  What does the electron do?

Or if the sudden change in motion is a problem, then instead what will
happen if an electron approaches a disk-magnet which is already spinning?

------

((((((((((((((((((((( ( (  (   (    (O)    )   )  ) ) )))))))))))))))))))))
William J. Beaty                                  SCIENCE HOBBYIST website
billb@eskimo.com                                  http://www.amasci.com
EE/programmer/sci-exhibits          science projects, tesla, weird science
Seattle, WA   206-781-3320          freenrg-L taoshum-L vortex-L webhead-L