If χ stands for the magnetic susceptibility of a given material, identify the class of materials for which:
(i)    – 1 ≥ χ < 0
(ii)    0 < χ < ε, (ε stands for a small positive number).
(a)    Write the range of relative magnetic permeability of these materials.
(b)    Draw the pattern of the magnetic field lines when these materials are placed in an external magnetic field.

(i) For – 1 ≥ χ < 0 i.e., magnetic susceptibilty is negative, the material is diamagnetic.

(ii) For 0 < χ < ε, material is paramagnetic.

(a) Range of relative magnetic permeability of diamagnetic material is 0 ≤ μ_r < 1. 

Range of relative magnetic permeability of paramagnetic material is 0 < μ_r < 1 + ε. 

(b) Fig. (1) shows the behaviour of magnetic field lines when diamagnetic material is placed in an external field.

Fig. (2) shows the behaviour of magnetic field lines when paramagnetic material is placed in an external field.