Question

How do we determine the poles for a ring magnet ?

Answer 1

If one knew the direction of the current through the ring then you could determine the direction of the magnetic field and hence the poles by using the right hand rule.

Answer 2

Consider the case of a permanent ring magnet. We could place a bar magnet whose poles are known into the middle of the ring magnet and note how the bar magnet aligns itself. The poles of the ring magnet will be opposite of the orientation of the bar magnet.

Answer 3

PeterAntimatter's solution is valid for an electromagnet.

Answer 4

thanks a lot