eddy currents. (1 Viewer)

[jeffwu95]

HSC board of studies 2011 sample answer:
As the magnets fall, they will produce a changing magnetic flux in the walls of both tubes. Lenz’s Law says that this will set up a current (eddy current) that will produce a magnetic field to try to oppose this change. This is possible for the magnet A tube, since the eddy current can flow around the complete circumference. This results in a strong braking force on the magnet. For the slotted tube, the eddy currents cannot flow because the slots break the current path and no braking results. This means that magnet B will fall faster and reach the end of the tube first.

There was also a multiple choice my that had 3 tubes, one slotted, one plastic and one metal. The answer said the plastic and slotted have the magnet fall at the same time...

I learnt is as eddy currents are produced but not as strong, which seems logical.

fucking physics.

My physics teacher said that the board of studies were stupid and it should slow down even with slots

 

[saleh1234]

This sums it all up, you wont need to refer to anything else...

http://lrrpublic.cli.det.nsw.edu.au...r/physics/lo/induction_08/induction_08_01.htm

 

[someth1ng]

Eddy currents definitely flow. The HSC tends to say that there are smaller eddy currents but no braking will occur however in reality, spme braking does occur.

 

[RishBonjour]

Yeah, I'm definitely writing that if such questions pop up. seems logical.