The gas which is used to produce and sustain powerful superconducting magnets, which form an essential part of Magnetic Resonance Imaging (MRI) system is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Helium
Helium has the lowest boiling point of all (4.2 K), so liquid helium can keep the magnet coils cold enough to stay superconducting.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Uses – “… Liquid helium (b.p. 4.2 K) finds use as cryogenic agent for carrying out various experiments at low temperatures. It is used to produce and sustain powerful superconducting magnets which form an essential part of modern NMR spectrometers and Magnetic Resonance Imaging (MRI) systems for clinical diagnosis.”