The amount of energy required to spin-flip a nucleus depends both on the strength of the external magnetic field and on the nucleus. At a field strength of 4.7 1 rf energy of 200 MHz is required to bring a 1H nucleus into resonance, but energy of only 187 MHz will bring a 19F nucleus into resonance. Calculate the amount of energy required to spin-flip a 19F nucleus. Is this amount greater or less than that required to spin-hip a 1H nucleus?