Assertion: The permeability of a ferromagnetic material is independent of the magnetic field.
Reason: Permeability of a material is a constant quantity.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and reason both are false.

Answer

D

Explanation

The permeability of a ferromagnetic material is not independent of magnetic field, `vec(B)= K_(m) vec(B)_(0)`
`B_(0)` is applied field. The total magnetic field `vec(B)` inside a ferromagnet may be `10^(3) or 10^(4)` times the applied field `B_(0)`. The permeability `K_(m)` of a ferromagnetic material is not constant, neither the field `vec(B)` nor the magnetization `vec(M)` increases linearly with `vec(B)`. Even at small value of `B_(0)`. From the hysteresis curve, magnetic permeability is greater for lower field.