$A$ ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet.
$(i)$ In which direction will it move?
$(ii)$ What will be the direction of its magnetic moment?

(N/A) Superconducting materials exhibit the Meissner effect,which makes them perfect diamagnets. When a superconducting material is placed in a magnetic field,it expels the magnetic field lines from its interior.
$(i)$ Due to the perfect diamagnetic property,the superconducting ball experiences a repulsive force from the bar magnet. Therefore,it will move away from the magnet.
$(ii)$ The induced magnetic moment in a diamagnetic material is always directed opposite to the external magnetic field. Thus,the direction of its magnetic moment will be opposite to the direction of the magnetic field produced by the bar magnet.