Question

A substance whose permeability is more than the permeability of free space is?

(a) Diamagnetic

(b) Paramagnetic

(c) Ferromagnetic

(d) Both paramagnetic and ferromagnetic

I have been asked this question during an internship interview.

This question is from Permeability of Free Space or Magnetic Constant in section Simple Magnetic Circuits of Basic Electrical Engineering

Answer 1

Right answer is (d) Both paramagnetic and ferromagnetic

Explanation: Relative permeability=1+Magnetic susceptibility

Since both paramagnetic and ferromagnetic materials have positive susceptibility, their relative permeability is greater than unity i.e. their permeability is more than the permeability of free space.