A magnetic needle suspended parallel to a magnetic field requires $$\sqrt 3 J$$ of work to turn it through 60^o. The torque needed to maintain the needle in this position will be

A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

A short bar magnet of magnetic moment 0.4 J T^$$-$$1 is placed in a uniform magnetic field of 0.16 T. The magnet is in stable equilibrium when the potential energy is

There are four light-weight-rod samples A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted
(i)  A is feebly repelled
(ii)  B is feebly attracted
(iii)  C is strongly attracted
(iv)  D remains unaffected

Which one of the following is true ?