Question

What is an approximation for the B-field of a bar magnet?

Answer 1

I've found the following equation in this source:
BN,S=μm4πr2N,S
Where r is the distance of "one pole"? I do not get how this can be well defined. The effective field is then something like
Beff=BN−BS.
Where S is the south pole and N the north pole.

I thought that the equation magnetic dipole would be the starting point for the derivation of the above formula - but I dont see how this formula can be transformed:
B⃗ =μ04π(3r⃗ (m⃗ r⃗ )r5−m⃗ r3)
The magnitude B is
B=μ04π(3mcos(α)r3−mr3).
Are Beff and B equivalent?

Hope this helps you ✌️ ✌️ ✌️....... pls mark as brainliest answer pls..............