學士後西醫物理及化學題庫下載題庫

60. MRI machine probes the concentration distribution of water molecules by detecting the magnetic resonance between the nucleus of hydrogen atoms, placed in a strong static magnetic field B, and a small alternating magnetic field of frequency f. If B is 2T and the z-component of the proton magnetic moment is J/T. What is the frequency f of the alternating magnetic field? (Plank constant is J/s)
(A) 43 MHz
(B) 85 MHz
(C) 170 MHz
(D) 340 MHz
(E) 680 MHz