Question

When a ferromagnetic material goes through a hysteresis loop, the magnetic susceptibility
(a) has a fixed value
(b) may be zero
(c) may be infinity
(d) may be negative

Answer 1

(b) may be zero
(c) may be infinity
(d) may be negative



We know,
$\mathrm{Magnetic}\mathrm{susceptibility}=\frac{I}{H}$
At point B, the value of H is zero but I is non zero. Magnetic susceptibility is infinity here. At point C, value of magnetic susceptibility will be negative. Here Magnetic field is applied in opposite direction to reduce the intensity of magnetization to zero. The applied field to reduce the residual magnetization to zero is called coercivity. At point D, I is zero but H is not zero so susceptibility of the material will be zero.