The desirable properties of materials for making permanent magnets ar…

The correct answer is Option (3) → high retentivity and high coercivity

Retentivity is the magnetisation that remains when the magnetising field is removed, and coercivity is the reverse field needed to destroy that magnetisation. A permanent magnet must stay strongly magnetised on its own and must not lose its magnetism easily, for example to stray fields, rough handling or temperature changes. So it needs both high retentivity and high coercivity, as in steel and alnico.

Option (1) low retentivity and high coercivity — Incorrect. With low retentivity the material keeps very little magnetism after the field is removed, so it makes a weak magnet.

Option (2) low retentivity and low coercivity — Incorrect. These are the properties of electromagnet and transformer cores (soft iron), which must lose their magnetism easily.

Option (3) high retentivity and high coercivity — Correct. Strong residual magnetism that is hard to remove is what a permanent magnet needs.

Option (4) high retentivity and low coercivity — Incorrect. With low coercivity a small opposing field demagnetises the material, so the magnet would not be permanent.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Permanent Magnets and Electromagnets – “… The hysteresis curve … allows us to select suitable materials for permanent magnets. The material should have high retentivity so that the magnet is strong and high coercivity so that the magnetisation is not erased by stray magnetic fields, temperature fluctuations or minor mechanical damage.”