Arrange the following materials in the ascending order of the values of their magnetic susceptibilities (χ).
(A) Diamagnetic
(B) Paramagnetic
(C) Soft ferromagnetic
(D) Hard ferromagnetic
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A), (B), (D), (C)
Magnetic susceptibility \( \chi \) measures how strongly a material is magnetised by an applied field, \( M = \chi H \).
(A) Diamagnetic: \( \chi \) is small and negative (about \( -10^{-5} \)), because the induced magnetisation opposes the field.
(B) Paramagnetic: \( \chi \) is small and positive (about \( 10^{-5} \) to \( 10^{-3} \)).
(D) Hard ferromagnetic: \( \chi \) is large and positive, but these materials (steel, alnico) are hard to magnetise.
(C) Soft ferromagnetic: \( \chi \) is the largest; materials such as soft iron are magnetised very easily by a small field.
So the ascending order is (A), (B), (D), (C).