Why do they vibrate and simply not get pulled closer or further from the source of emf?
This may be related to the shape, but if I take a small N45 disc magnet and put it near an electrical appliance, the magnet will vibrate. The intensity of the vibrations varies depending upon where you move the magnet as well.
Is there an optimal magnet shape to generate the strongest vibrations?
I assume there is at least an optimal mass/magnetic strength ratio for the strongest vibrations?