This work provides a missing manual needed to understand permanent magnets (also known as “hard” magnets), the only source of magnetic induction field B (units of teslas), often called the magnetic field, that students are familiar with when they confront magnetic force acting on moving charges. Students see this magnetic force in two forms:
References
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There are two distinct kinds of induction. Electrical induction is the polarization of electrical conductors, associated with a noncirculating electric field. Magnetic induction refers to the circulating electric field caused by a time-varying magnetic field.
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16.
I have read somewhere (I can no longer trace its origin) of the following clever geometry; I recall it was Coulomb, but I might be mistaken. Place two nominally identical magnets side by side with N–N and S–S opposite, fixing the lower one in place on the track, and letting the upper one slide on the track. In equilibrium, a component of the upper magnet’s weight is balanced against the magnetic repulsion. The attractive forces due to the more distant N–S and S–N poles make a small angle to the common direction of their axes, and therefore give only a small net attractive force between the magnets. In contrast, for magnets in a line, the force between distant poles is much larger, requiring more significant corrections.
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(2013
).© 2022 Author(s). Published under an exclusive license by American Association of Physics Teachers.
2022
Author(s)
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