A magnet of magnetic moment 20 C.G.S. units is freely suspended in a uniform magnetic field of intensity 0.3 C.G.S. units. The amount of work done in deflecting it by an angle of ${30}^o$ in C.G.S. units is
(a) 6

(b) $3\sqrt{3}$

(c) $3(2-\sqrt{3})$

(d) 3

The magnetic field due to a short magnet at a point on its axis at distance X cm from the middle point of the magnet is 200 Gauss. The magnetic field at a point on the neutral axis at a distance X cm from the middle of the magnet is
(a) 100 Gauss               (b) 400 Gauss
(c) 50 Gauss                 (d) 200 Gauss

A magnet of magnetic moment $50\widehat{i }A-m^2$ is placed along the x-axis in a magnetic field $\overrightarrow{B}=(0.5\hat{i}+3.0\hat{j})T$. The torque acting on the magnet is

(a) 175 $\hat{k}$ N-m

(b) 150 $\hat{k}$ N-m

(c) 75 $\hat{k}$ N-m

(d) 25$\sqrt{37}$ $\hat{k}$ N-m