Magnetism and Matter

An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity $$B$$, the magnetic field $$B_{s}$$ inside the superconductor will be such that
The magnetic induction due to a magnetic pole of pole strength 1500 A-m at a distance of 50 cm is:
A coil and a bulb are connected in series with a dc source, a soft iron core is then inserted in the coil, then 

Maximum P.E. of magnet of moment M situated in a magnetic field of induction B, is

When a D.M. is set in $$\tan A$$ position, the deflection is $$30^{o}$$ for a magnet A placed at a distance of $$40\ cm$$ from the midpoint of the D.M. When the D.M. is kept in $$\tan B$$ position another magnet B produces a deflection of $$60^{o}$$, when placed at the same distance. The ratio of the magnetic moments of A and B is :