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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: supermanflyaway on November 10, 2012, 10:26:50 pm

Title: Change in flux
Post by: supermanflyaway on November 10, 2012, 10:26:50 pm
When the south pole of a magnet is put through a loop of wire, is the flux increasing, even though the magnetic field lines don't really pass into the loop?
Title: Re: Change in flux
Post by: meemz on November 11, 2012, 12:49:50 am
wouldn't the magnetic field be in the opposite direction, meaning it will have an increasing flux? 
Title: Re: Change in flux
Post by: supermanflyaway on November 11, 2012, 10:46:21 am
When the south pole of a magnet is put through a loop of wire, is the flux increasing, even though the magnetic field lines don't really pass into the loop?

When a south pole is pushed through the loop, the flux is decreasing. What I mean is that assume you're holding a magnet so that the south pole is facing away from you, then moving it directly into the loop.

This might seem weird but for example field lines are just a human's way of conceptualizing the topic.

So pushing a magnet through a loop north pole first means the flux is increasing, while south pole first means the flux is decreasing (negative flux)?
Title: Re: Change in flux
Post by: golden on November 11, 2012, 11:03:36 am
Here's a way of thinking about it:
In terms of generating a current, moving a north pole of a magnet in is equivalent to moving the south pole out.
Likewise moving a south pole in is equivalent to moving the north pole out.

Faraday's Law states that:
emf = -N(change in flux)/dt

Edit: grammar