Positively charged alpha particles move in a circular path with a radius of about 4.0 cm under the influence of a magnetic field with a strength equal to about 1.0 T. What magnitude and direction for an applied electrical field would cause these alpha particles' trajectory to become linear? [Hint: The mass of an alpha particle = 6.644 × 10^-27 kg, the charge of an alpha particle = +2 ×1.602 × 10^-19 C.]

A mass spectrometer uses sulfur isotopes of mass numbers 32, 33, and 34 from a meteorite sample. The electric field between the plates is 2.9×10⁴ V/m and the magnetic fields are B = B' = 0.60 T and their directions are shown below. To estimate atomic masses, multiply by 1.67×10⁻²⁷ kg. How far apart are the marks formed by singly charged ions of each type on a detector film? Hint: The mass m of an isotope in this spectrometer is equal to qBB'r/E and charge q=1.602×10^⁻19 C.

A mass spectrometer uses sulfur isotopes of mass numbers 32, 33, and 34 from a meteorite sample. The directions of the electric field between the plates and the magnetic fields are shown below. The marks formed by singly charged ions of each type on a detector film are equally spaced based on this expression: $2r=\frac{2mE}{qBB^{\prime }}$. Does it matter if the ion charge is positive (lost electrons) or negative (gained electrons)? Explain.