For a mass spectrometer the magnetic field is varied to allow ions of varying mass to reach the detector. A different method would be to maintain a constant magnetic field and vary the accelerating potential difference of V. Assuming the magnetic field is held at B= .250T and that r= .0750 m in which of the following ranges of voltages could one detect both oxygen molecules (m=2.656 x 10^-26kg) and nitrogen molecules (m= 2.325 x 10^-26kg)