An iron rod of susceptibility 599 is subjected to a magnetizing field of 1200 A m^-1. The permeability of the material of the rod is :
$$\left( {{\mu _0} = 4\pi \times {{10}^{ - 7}}Tm{A^{ - 1}}} \right)$$

At a point A on the earth’s surface the angle of dip, $$\delta $$ = + 25^o. At a point B on the earth's surface the angle of dip, $$\delta $$ = – 25^o. We can interpret that :

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from

A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 $$\mu $$A and subjected to a magnetic field of strength 0.85 T. Work done for rotating the coil by 180^o against the torque is