Meissner effect (1 Viewer)

[NizDiz]

When a question is asked about why magnet hovers above superconductor, is it just due to exclusion of magnetic fields? or Eddy currents produced to? (even thought that's wrong), what about quantum pinning? can we mention that?

 

[someth1ng]

Depending on the situation but typically, exclusion of magnetic fields.

 

[NizDiz]

so that is the main thing needed to say then?

 

[coyney]

I thought it was the repulsion of magnetic fields?

 

[Fizzy_Cyst]

When a question is asked about why magnet hovers above superconductor, is it just due to exclusion of magnetic fields? or Eddy currents produced to? (even thought that's wrong), what about quantum pinning? can we mention that?

Exclusion of magnetic fields.

Quantum pinning / flux trapping is beyond the syllabus, I talked about it with my class as it is a more complete representation of what really happens and why it is not really a repulsion, but a repulsion and attraction, but I stressed that it is BEYOND the syllabus and if a question asks you to explain why it hovers this is what you need to say.

- exclusion of magnetic fields from interior of superconductor due to Meissner Effect (creation of current inside SC to oppose external mag field)

AND

- weight force is balanced by magnetic repulsion force between magnet and SC so that it hovers

That is pretty much what it said in a HSC marking scheme for hat particular question (was a 3-marker). If you are given a higher mark question about it, for sure, mention flux trapping! As it shows that you went ABOVE AND BEYOND!

 

[kalstar]

Yeah I was confused about this too, however I believe it's due to the exclusion of magnetic fields ^