what is ring magnet?

Answer 1

a magned in the shape of a ring. a bar magnet is in the shape of a bar and a horse shoe magnet is in the shape of a, you guesed it, horse shoe.

by changing the shape of the magnet you can control where the field lines go and this is useful for different applications. a bar magnet is good for the needle in a compas. a ring magnet is good for a solonoid.

Answer 2

A toroidal (circle) shaped magnet usually made of ferrite or by running a wire(and current) through a ferrite hole.Used in old(50's/60's) main frame RAM's