Cut a bar magnet in half and you never get a loose north pole and a loose south pole, only two smaller magnets that each have both. The reason lies inside: the material is divided into countless magnetic domains, and the stronger the applied field the more of them rotate into alignment, while heating past the Curie point scrambles them again and the bar loses its magnetism. Faraday supplied the remaining crucial point: a magnet sitting still inside a coil leaves the meter needle at zero, since only a changing flux can generate an EMF.
Cut a bar magnet in half and you never get a loose north pole and a loose south pole, only two smaller magnets that each have both. The reason lies inside: the material is divided into countless magnetic domains, and the stronger the applied field the more of them rotate into alignment, while heating past the Curie point scrambles them again and the bar loses its magnetism. Faraday supplied the remaining crucial point: a magnet sitting still inside a coil leaves the meter needle at zero, since only a changing flux can generate an EMF.
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