Is the permeability of a ferromagnetic material independent of the magnetic feld? If not, is it more for lower or higher fields?

Resultant force acting on a diamagnetic material in a magnetic field is in direction

A small bar of ferromagnetic substance placed in a non-magnetic field then in which direction does it move ?

A Rowland ring of mean radius 15 cm has 3500 tums of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?

What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building 'memory stores in a modern computer?

Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?

The region inside a current carrying torodial winding is filled with tungsten of susceptibility 6.8 xx 10^(-5) . What is the percentage increase in the magnetic field in the presence of the material with respect to the magnetic field without it ?