Needles N1 , N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively.
Needles N1 , N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will
(a) attract all three of them
(b) attract N1 and N2 strongly but repel N3
(c) attract N1 strongly, N2 weakly and repel N3 weakly
(d) attract N1 strongly, but repel N2 and N3 weakly
2 Answers
Correct Option(c) attract N1 strongly, N2 weakly and repel N3 weakly
Explanation:
Ferromagnetic substances have strong tendency to get magnetised (induced magnetic moment) in the same direction as that of applied magnetic field, so magnet attracts N1 strongly.
Paramagnetic substances get weakly magnetised (magnetic moment induced is small) in the same direction as that of the applied magnetic field, so magnet attracts N2 weakly.
Diamagnetic substances also get weakly magnetised when placed in an external magnetic field but in the opposite direction and hence N3 is weakly repelled by a magnet.