The work done in turning a magnet of magnetic moment M by an angle of 90° from the meridian, is n times the corresponding work done to turn it through an angle of 60°. The value of n is given by(a)2(b)1(c)0.5(d)0.25

(a)

Magnetic moment = M; Initial angle through which magnet is turned (q₁) = 90° and final angle through which magnet is turned (q₂) = 60°. Work done in turning the magnet, through 90^o(W₁) = MB (cos 0° - cos 90°)

= MB (1-0) = MB.

Similarly, W₂ = MB (cos 0° - cos 60°)