ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: Gilla1 on July 12, 2011, 06:33:10 pm

Title: Difference between placing a compass above and below a current carrying wire?
Post by: Gilla1 on July 12, 2011, 06:33:10 pm

What difference would it make to a compass needle to have it in these two positions?

Title: Re: Difference between placing a compass above and below a current carrying wire?
Post by: appianway on July 12, 2011, 07:16:55 pm

Basically, the external fields (neglecting the earth's magnetic field) will be in opposite directions.

Title: Re: Difference between placing a compass above and below a current carrying wire?
Post by: Gilla1 on July 12, 2011, 07:50:11 pm

is that something we're supposed to just know or do we have to know why? :S
why would it be in opposite directions if the current is still going the same way? D:

Title: Re: Difference between placing a compass above and below a current carrying wire?
Post by: appianway on July 12, 2011, 07:52:48 pm

It's basically to do with the shape of the field around a current carrying wire. Basically, the field "curls" around the wire in a circle, so if the field is clockwise, the field at the top will be pointing to the right and the field at the bottom will be pointing to the left.