From: Mark Lawton (markslawton@hotmail.com)
Date: Fri Nov 15 2002 - 11:09:11 PST
Date: Fri, 15 Nov 2002 11:09:11 -0800 Subject: Re: Pinhole Digest #1060 - 11/15/02 From: Mark Lawton <markslawton@hotmail.com> Message-ID: <B9FA8657.2CF3%markslawton@hotmail.com>
>
> 5. Does a battery have a small magnet inside it? Why does a compass move
> when a 9V battery is brought close to it?
a battery has a voltage and therefore an electric field. when an electric
field moves by a conductor (the needle) or a conductor moves by an electric
field a current is induced in the conductor. the induced current creates
its own magnetic field which opposes the original magnetic field. this is
called induction. the changes in mag field make the compass needle move.
using induction, one could steal electricity from the electric company
simply by putting a conductor near a power line. unfortunately the power
company would discover that electricity is "leaking" and the thief would be
reprimanded.
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