Re: Lights in compass?

[roger haar <haar@soliton.physics.arizona.edu>]

 Hi,

	My first guess without seeing the lighted compass, is that the 
wires ( +, - ) run side by side, so the field from one is mostly canceled
by the other.  They could even be twisted together for better cancelation. 

Thanks
roger haar
Physics U of AZ.



***********************************************************************
On Tue, 21 May 1996, JONATHAN GILLIS wrote:

> A student brought this up in class yesterday when we were doing Oersted's 
> experiment with wires and compasses to see the magnetic fields created by 
> wires.  He said that he (or his family) has a boat with a compass.  The 
> compass has a light in it so you can see it at night.  He asked if the 
> wire carrying current to the light (and I guess the filament itself) 
> would generate a field that would disrupt the compass.  The question made 
> sense.
>
> Doesthe wire effect the compass?  If not, how is it avoided?  Is it just 
> small enough to ignore?
>
> Thanks in advance for any comments!
>
> Jonathan Gillis
> Enloe High School
> Raleigh, NC
> gillis@avalon.nando.net