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A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by ${60}^{\circ }$ is W. Now the torque required to keep the magnet in this new position is

(a) $\frac{W}{\sqrt{3}}$                    (b) $\sqrt{3}W$

(c) $\frac{\sqrt{3}W}{2}$                (d) $\frac{2W}{\sqrt{3}}$

NEET