In the operating room, anesthesiologists use mass spectrometers to monitor the respiratory gases of patients undergoing surgery. One gas that is often monitored is the anesthetic isoflurane (molecular mass = 3.06 x 10-25 kg). In a spectrometer, a singly ionized molecule of isoflurane (charge = +e) moves at a speed of 4.00 x 103 m/s on a circular path that has a radius of 0.05 m. What is the magnitude of the magnetic field that the spectrometer uses?