Why does a paramagnetic sample display greater magnetistion (for the same magnetising field ) when cooled ?

Why does the paramagnetic nature of the 3d transition series increase till Cr and then decrease regularly?

Why does a diamond sparkle with great brilliance? Or, Why does a diamond cut in the same fashion shine more brightly than a piece of glass?

If the magnetic moment of a straight magnetised wire is p_(m) , what will be its magnetic moment when the wire is bent in the form of a semicircle ?

In a ferromagnetic substance a magnetising force field of 360 Am^-1 produces a magnetic flux density of 0.6 T. The magnetic susceptibility of the substance is—

(a) Magnetic field lines show the direction (at every point) along which a small magnetised needle aligns at the point). Do the magnetic field lines also represent the lines of force on a moving charged particle at every point? (b) Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. Why? (c) If magnetic monopoles existed, how would the Gauss's law of magnetism be modified? (d) Does a bar magnet exert a torque on itsell due to its own field? Does one element of a current-carrying wire exert a force on another element of the same wtre? (e) Magnetic field arises due to charges in motion. Can a system have magnetic moments even though its net charge is zero?

Which of the following substances can exist in a permanently magnetised state even when the magnetic field is removed, and why? (i) Paramagnetic (ii) Ferromagnetic (iii) Ferrimagnetic