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Homework Help: Finding the mass of an atom - bainbridge mass spectrometer question

  1. Jul 28, 2009 #1
    Q. In a particular spectrometer, doubly ionised [tex]\stackrel{12}{6}[/tex]C and singly ionised [tex]\stackrel{6}{3}[/tex]Li atoms are detected. The ratio of the path radii is 1.00252, the Li having the larger value. The fields are constant. Find the mass of of the lithium atom.

    I can only think of the equation which links electric force and circular motion in order to find the mass of the atom, however I cant seem to draw out the info needed to use the equation:

    m = q [tex]\frac{BR}{v}[/tex]

    where q is the charge, B is the magnetic field, and v is the velocity of the atom.
  2. jcsd
  3. Jul 28, 2009 #2


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    It's just a ratio thing.
    What do you know about the mass of a Carbon12 atom (hint think standards)
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