Arrange the following substances in the increasing order of magnetic susceptibility.
(A) Paramagnetic substances
(B) Superconductors
(C) Diamagnetic substances
(D) Ferromagnetic substances
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (B)<(C)<(A)<(D)
The magnetic susceptibility \( \chi = M/H \) is negative for diamagnetic materials and positive for paramagnetic and ferromagnetic ones. Ordering the four substances from the most negative to the most positive value:
(B) Superconductors — a superconductor is a perfect diamagnet with \( \chi = -1 \), the lowest value of all.
(C) Diamagnetic substances — \( \chi \) is small and negative (of the order of \( -10^{-5} \)).
(A) Paramagnetic substances — \( \chi \) is small and positive (of the order of \( +10^{-5} \)).
(D) Ferromagnetic substances — \( \chi \) is large and positive, the highest of all.
The order is therefore (B) < (C) < (A) < (D).
NCERT (2026-27):
Magnetic Properties of Materials – “… In terms of the susceptibility χ, a material is diamagnetic if χ is negative, para- if χ is positive and small, and ferro- if χ is large and positive.”
Diamagnetism – “… The most exotic diamagnetic materials are superconductors. These are metals, cooled to very low temperatures which exhibits both perfect conductivity and perfect diamagnetism. Here the field lines are completely expelled! χ = –1 and μr = 0.”