Magnet types & field homogeneity (permanent/resistive/superconducting)
A three-column comparison table of MRI magnet types. Permanent magnets: about 0.2 to 0.4 tesla, no cryogens, no power to hold the field, small fringe field contained by an iron yoke, open bore. Resistive electromagnets: up to about 0.3 to 0.5 tesla, no cryogens, need continuous power but switch off instantly, small shielding-dependent fringe field, open bore. Superconducting magnets: 1.5 to 3 tesla or more, need liquid helium at about 4 kelvin, no power once ramped due to persistent current, large fringe field needing active shielding, closed long bore.
Practice the Physics paper
FRCRX is a Part 1 Physics question bank: true/false items with explanations, timed mocks and topic analytics.