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for the shaded-pole motor, our rotatable disk is paramagnetic, so it must be attracted to the magnetic field of the inductor. but in the question it said it repelled. does that para disk increase the B and because of this it will be repelled by the Lenz's law?! enter image description here

glS
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Farinaz Talebi
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If the magnetic field were static then the paramagnetic copper disk would indeed be attracted into it. However an oscillating magnetic field will generally repel conducting materials. This is because the oscillating field induces eddy currents in the conductor and the eddy currents in turn generate a magnetic field that repels the original field.

This process is the basis of magnetic levitation. See in particular the section of this article on oscillating fields.

John Rennie
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