A sample containing protons is exposed to an r.f. magnetic field with peak amplitude B RF = 469.8 T.

A sample containing protons is exposed to an r.f. magnetic field with peak amplitude B RF = 469.8 T. The frequency of the r.f. field is exactly resonant with the proton Larmor precession. (i) What is the nutation frequency of the protons in units of hertz? (ii) How long should the r.f. field be applied in order to generate a pulse with a flip angle of p/2? (iii) What is the flip angle of the protons if the pulse duration is kept as in (ii) but the peak r.f. field is increased to B RF = 939.6 T?