Understanding B and H Fields: A Thought Experiment on Magnetic Field Propagation

[rxwontfit]

Hey everyone,

I'm learning about B and H fields in electromagnetic waves and propagation class. Trying to wrap my head around the idea that magnetic fields wrap around current carrying wires.

Consider this:

If you were to take a clear, hollow cylinder, drill a hole at both ends, run a copper wire concentrically down the middle, fill it with baby oil and iron filings and seal both ends.

Then energize the wire with a voltage so that constant current flows...

Describe the movement of the iron filings.

I'm curious - will they actually start moving in circles around the wire?

Cheers and Thanks!

JoAr

 

[dlgoff]

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html"

A picture is worth a 1000 words. In this case anyway.

 

[rxwontfit]

I know this.
That doesn't answer my question.

To say that B will circle the wire - does it imply that the iron filings will actually start moving in circles around the wire? Aka will they actually receive a constant angular force? Or will they simple orient themselves in a circular fashion and sit there?

Thanks,

JoAr

 

[dlgoff]

They will line up in a circular pattern as represented by the blue arrows. With a constant current in the conductor, the fillings will just arrange in that pattern and set there. Notice that each filling will actually be magnetize with it polarization (north/south) determined by use the "right hand thumb rule" as illustrated.