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Homework Help: Charge-to mass ratio

  1. Jun 1, 2010 #1
    1. The problem statement, all variables and given/known data
    1.Sketch a diagram of the atom He3, using the appropriate quarks and leptons.

    2 The charge-to-mass ratio of the pion was determined in 1. The charge-to-mass ratio of the electron is 1.76 x 10^11 C/kg.
    a) Based on this info, predict which particle has a greater mass- the electron of the pion . Justify your answer by referring to the charge-to-mass ratio.
    b) Use the value of the elementary charge (e = 1.6 x 10^-19C) to calculate the mass of the pion in kg. Compare the mass of the pion to the mass of the electron.

    2. Relevant equations
    q = q/m x m

    3. The attempt at a solution
    1. No problems, just stated question to illustrate entire problem

    2a) I predict the He3 particle will have more mass- it consists of 2 protons, 1 neutron and 2 electrons

    2b) mass of electron = charge/ charge to mass ratio
    = (1.6 x 10^(-19) C)/(1.76 x 10^11 C/kg)
    = 9.09 x 10-31 kg
    It's the pion charge-to-mass ratio I'm having troubles with. Between the quarks and leptons- it is a neutral atom, therefore dividing the charge by the mass is 0
    I feel like I've been at this too long, and I'm missing a basic point here.
    Please help
    Last edited: Jun 1, 2010
  2. jcsd
  3. Jun 1, 2010 #2
    There is not enough information to formulate an intelligible reply.
  4. Jun 2, 2010 #3
    The Pion is not an atom, it is a meson.

    Pions can have ±1 elementary charge. That is the charge to mass ratio the question is referring to. This is something you should have, according to the question.
  5. Jun 2, 2010 #4
    So the pion is a meson of the He3 atom?
    Can't pions also have a 0 charge? +1, -1 or 0 charge?
    Thank you for your help.
  6. Jun 2, 2010 #5
    The charge-to-mass ratio was not provided. It was to be determined trhrough my sketch in #1. The sketch shows that the quarks and leptons cancel each other out to leave the meson with a 0 charge
  7. Jun 2, 2010 #6
    How does sketching a He3 atom provide you with data on a pion?

    Consider the following, there are three kinds of pions, [tex]\pi ^ 0, \pi ^{-}, \pi^{+}[/tex]
  8. Jun 2, 2010 #7
    I figured that since it helped me to see that the quarks and leptons cancel out each other, it shows a 0 charge. Since the ratio is q/m and q = 0 then the ratio = 0.
  9. Jun 2, 2010 #8
    How exactly is this equation supposed to help solve the problem?
  10. Jun 2, 2010 #9
    mass = charge/ charge to mass ratio
    is what I got from that equation, and I used this to help me determine the mass of the electron.
    I am supposed to compare the mass of pion to the mass of the electron, so I needed to determine the mass of the electron.
  11. Jun 2, 2010 #10
    This is my final question in my ILC course (other than my unit summary) before I prep for my final. I haven't NOT answered any questions yet, and I could really use some help to understand what I'm just not getting about this one.
    Any input would be helpful please.
    Thank you
  12. Jun 3, 2010 #11
    A Pion has very little in common with He3, is the problem.
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