Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jeffreyH on 09/09/2014 01:06:44

Title: What happens when we put bar magnets together
Post by: jeffreyH on 09/09/2014 01:06:44
The divergence of the magnetic field is zero and we have a circularity in the field. What happens when we put two bar magnets together north pole to south pole. Do they combined into one continuous field or do the two separate fields still exists?
Title: Re: What happens when we put bar magnets together
Post by: chiralSPO on 09/09/2014 06:04:02
You can always add up multiple fields from different magnets to give one total field, regardless of the number or orientation of the magnets. Is the field continuous? Barring some pretty bizarre circumstances, I think it would be yes, no matter the number or orientation of the magnets.
Title: Re: What happens when we put bar magnets together
Post by: jeffreyH on 09/09/2014 17:23:51
The question was posed in such a way that answers would be useful to those wanting to learn. What I am interested in are the changes in the field lines as the magnets come closer together. Ultimately the surfaces touch and the two circular fields would combine, I expect. I have seen no data for this online.
Title: Re: What happens when we put bar magnets together
Post by: RD on 09/09/2014 19:03:52
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Ftsgphysics.mit.edu%2Fpics%2FG%2520Magnetic%2520Fields%2FG2-Bar-Magnet-broken-edited-sm.jpg&hash=d1f0c3c2868fea0b9af17ddd08b69b51)
http://tsgphysics.mit.edu/front/?page=demo.php&letnum=G%202 (http://tsgphysics.mit.edu/front/?page=demo.php&letnum=G%202)

Magnetic field viewing film (http://en.wikipedia.org/wiki/Magnetic_field_viewing_film) is less messy than loose iron filings.
Title: Re: What happens when we put bar magnets together
Post by: jeffreyH on 09/09/2014 20:45:08
The film looks better. I think orienting it properly would be a bit of a pain.
Title: Re: What happens when we put bar magnets together
Post by: PmbPhy on 09/09/2014 21:00:48
Quote from: jeffreyH
The divergence of the magnetic field is zero and we have a circularity in the field.
It's not called "circularity" it's called "circulation, i.e. the curl is not zero. With the magnetic field that only happens when B is an explicit function of time.

Quote from: jeffreyH
What happens when we put two bar magnets together north pole to south pole. Do they combined into one continuous field or do the two separate fields still exists?
The separate fields add vectorially to form one continuous field.