Question

A large magnet is broken in to two pieces so that their length are in ratio 2:1 . the pole strength of the two piece will be 1 in the ratio 4:1 2 in the ratio 2:1 3 in the ratio 1:2 4 equal

Answer 1

Answer:

Strength of the pole due to the magnetic charge qm at a distance r is given by

μ0qm/4πr^2 ......(1)

This equation is derived for a solenoid, the same results can  

be applied to a bar magnet as they both produce similar magnetic fields.

From equation (1) it is clear that magnetic pole strength doesn't depend on the  length of the bar magnet.

Hence even after breaking the ratio of the magnets pole strength will be 1:1