The behaviour of magnetic field lines in the presence of
(i) paramagnetic and
(ii) diamagnetic substances. How does one explain this distinguishing feature?
Magnetic permeability of paramagnetic substance is more than air, so it allows more lines to pass through it while permeability of diamagnetic substance is less than air, so it does not allow lines to pass through it. Thus, diamagnetic substances expel magnetic field lines, while paramagnetic substances attract them.