<prompt> NMR is based on the principle ofElectron beamProton beamNeutron beamMagnetic field  <response>: The phenomenon of nuclear induction, later to be termed nuclear magnetic resonance NMR, was described by Bloch and Purcell and their colleagues in 1946. NMR has been used extensively for studying the propeies of matter at the molecular level NMR spectroscopy. In applications to medicine, the term nuclear has been dropped, leaving it as magnetic resonance or MRRef: Grainger;s diagnostic radiology, 6th ed; page 90 