Explaining Meissner Effect (1 Viewer)

QZP

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How do you explain the Meissner effect? I believe it is wrong to explain the Meissner effect as the induction of currents which perfectly oppose the relative motion of the magnet (Lenz's Law) thereby excluding any magnetic flux within the superconductor in superconducting state. This is wrong because you can place a magnet on top of a cooling superconductor, and it will begin to levitate once the superconductor is below critical temperature i.e. it levitates without experiencing a rate of change in flux. So what does the HSC want? To take the Meissner effect as some magical phenomenon?
 

Fizzy_Cyst

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Ahhhh yes...

Meissner and Lenz... I have seen trial papers where marking guidelines say that you MUST talk about Induction with the Meissner Effect :\

They are quite different things! Lenz arises due to rate of change of flux, Current loops in the Meissner effect arise due to flux in general.

Best thing to say is that Meissner Effect arises due to the opposition of a superconductor below Tc to magnetic flux incident on it, current loops are created to produce a flux to oppose the flux incident on the SC, thus causing net flux through the SC to be zero.

I got a cool question for you.. In that scenario where you gave the magnet rising as the SC cools, this causes the magnet to increase its GPE.. Where does this energy come from? :)
 

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