JEE MAIN - Physics (2006 - No. 7)
Needles $${N_1}$$, $${N_2}$$ and $${N_3}$$ are made of ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will
attract $${N_1}$$ and $${N_2}$$ strongly but repel $${N_3}$$
attract $${N_1}$$ strongly, $${N_2}$$ weakly and repel $${N_3}$$ weakly
attract $${N_1}$$ strongly, but repel $${N_2}$$ and $${N_3}$$ weakly
attract all three of them
Uitleg
Ferromagnetic substance has magnetic domains whereas para-magnetic substances have magnetic dipoles which get attracted to a magnetic field. Diamagnetic substances do not have magnetic dipole but in the presence of external magnetic field due to their orbital motion of electrons these substances are repelled.