A uniform conducting wire of length 12a and resistance 'R' is wound up as a current carrying coil in the shape of ,

(i) an equilateral tringle of side 'a'

(ii) A square of side 'a'

The magnetic dipole moments of the coil in each case respectively are :

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