Question

Does magnetism require a "non-uniform" magnetic field? Because in Prof Lewin's demonstration of ferromagnetism with an aluminum bar, he uses a non-uniform magnetic field. Thanks! @Physics

Answer 1

The question itself is nonsensical. Perhaps an elucidation of the physics will illustrate this and dissolve the question altogether. (Classically & over simplistically) Magnetism is a phenomena in which a moving charged particle experience a force (Lorentz Force) due to a magnetic field. The source of a magnetic field is the movement of another charged particle. In the case of bar magnets it is the spin of the electrons of the atoms making up the bar. It is the arrangement of the movements of such charges that determines the shape of the magnetic field which may or may not be uniform.

For example the magnetic field is uniform inside a solenoid.

Answer 2

dude which is the standard u r studying in?? if possible go through the quantum theory of ferromagnetism.hope you'll clear your doubts after dat.

Answer 3

thanks guys! i was just confused by why Prof Lewin kept on emphasizing that he was using a non-uniform magnetic field