Which of the following statements related to magnetic materials are correct?
A. Diamagnetic materials get strongly magnetized in an external magnetic field.
B. Ferromagnetic materials get strongly magnetized in an external magnetic field.
C. Paramagnetic materials get weakly magnetized in an external magnetic field.
D. Soft iron is a suitable material for the core of electro-magnets.
E. For diamagnetic materials, magnetic susceptibility is positive and small.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B, C, D only
Magnetic materials are classed by their magnetic susceptibility \( \chi \): diamagnetic \( \chi \) small and negative, paramagnetic \( \chi \) small and positive, ferromagnetic \( \chi \) large and positive.
A. Diamagnetic materials get strongly magnetized in an external magnetic field. — Incorrect. Diamagnetic materials are only weakly magnetised, and in the direction opposite to the applied field.
B. Ferromagnetic materials get strongly magnetized in an external magnetic field. — Correct. Their domains align with the field, giving a very large magnetisation.
C. Paramagnetic materials get weakly magnetized in an external magnetic field. — Correct. Their atomic dipoles align only partly against thermal agitation, so the magnetisation is weak, in the direction of the field.
D. Soft iron is a suitable material for the core of electro-magnets. — Correct. Soft iron has high permeability and low retentivity, so it gives a strong field while the current flows and loses its magnetism when the current is switched off.
E. For diamagnetic materials, magnetic susceptibility is positive and small. — Incorrect. For diamagnetic materials \( \chi \) is small and negative; small and positive \( \chi \) is for paramagnetic materials.
Note: Statements (A), (B), (C) and (E) of this question are from the latest textbook (2026-27). Statement (D), that soft iron is a suitable material for the core of electro-magnets, is printed only in the pre-rationalised textbook (2022-23). It was removed from the latest book, and it also appears to be out of the CUET 2026 syllabus.
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.”
Paramagnetism – “Paramagnetic substances are those which get weakly magnetised when placed in an external magnetic field.”
Ferromagnetism – “Ferromagnetic substances are those which gets strongly magnetised when placed in an external magnetic field.”
NCERT (Pre-rationalised edition, 2022-23):
Permanent Magnets and Electromagnets – “… Core of electromagnets are made of ferromagnetic materials which have high permeability and low retentivity. Soft iron is a suitable material for electromagnets.”