Re: is the magnetic field really moving?

On 15 Aug, 00:03, Christoph Kobe <christ...@[EMAIL PROTECTED]
> wrote:
> On Thu, 14 Aug 2008 17:38:09 -0500
> "Terry L Hewett Sr" <terrylhewet...@[EMAIL PROTECTED]
> wrote:
>
> > "Christoph Kobe" <christ...@[EMAIL PROTECTED]
> wrote in message
> >news:20080814212631.3f00a56a.christoph@[EMAIL PROTECTED]
>
> > > I don't agree with you that there is a second field generated in the
iron.
> > > Why should it be there?
>
> > The iron is not only conductive it is a ferrite. It will induce the
field
> > from the wire through conductive properties carried by the field. This
is a
> > simple experiment wind a coil around a 1/2 inch bolt apply voltage.
see if
> > you don't see a second field generated by the bolt. The same would be
true
> > if you wound the coil inside of a iron pipe, however it is more
efficient to
> > have the iron core within the coil.
>
> Well, the comparision (winding a wire around bolt) is really bad,
because
> 1. The winding is not around a ferrit, it's only in a part of it. That
would
> be drilling a hole through the bolt, putting the coil through that hole
and only
> around half of the bolt. The flux would be 'shortened' by the other half
of the
> bolt, thus not generating a field outside the bolt.
> 2. In this case there is only one winding and one winding is by far not
> enough to cancel the other magnetic field (unless you put more than
10000 A through it ...).
> 4. We're only talking about voltage induction. No current yet. No
current means, no additional
> magnetic field generated.

> Conclusion: Theory that there is a sencond opposing field generated is
wrong.

When a field is applied to iron, it has the effect of aligning the
domains - tiny bar magnets - within it so that they collectively add
to the applied field. The effect is to intensify the total magnetic
field within the iron, but decrease it external to the iron.

Get a U magnet and add small bar magnets between the ends. The fields
of the U magnet and that of the bar magnets add to give little
external field but an intense field within the bar magnets.