What does the analog (similarity) of bar magnet’s and solenoid’s magnetic field lines suggest ?

Two like magnetic poles of strength $ 10$  and $40$ $ SI$ units are separated by a distance $30 \,cm$. The intensity of magnetic field is zero on the line joining them

Two short bar magnets of magnetic moments ' $M$ ' each are arranged at the opposite corners of a square of side ' $d$ ', such that their centres coincide with the corners and their axes are parallel to one side of the square. If the like poles are in the same direction, the magnetic induction at any of the other corners of the square is

Give some of the commonly known ideas regarding magnetism.

Two bar magnets having same geometry with magnetic moments $M$ and $2 M$, are firstly placed in such a way that their similar poles are same side then its time period of oscillation is $T_{1}$. Now the polarity of one of the magnet is reversed then time period of oscillation is $T_{2},$ then