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Homework Help: Qns On Protons

  1. May 17, 2006 #1

    Given that a " up " quark has charge of 2/3e ; a "down" quark has a charge of - 1/3e, where e is the elementary charge (+1.6 x 10^-19 C).

    can is say that a proton contain 3 " up " quark and 1 "down" quark?

    the charge in the end seems to add up to +1.

    is what is have said correct?

    p.s. i just started learning particle physics
  2. jcsd
  3. May 17, 2006 #2
    (3 x 2/3) + (1x(-1/3)) = 1?

    Incase you meant 3 down quarks, then that doesn't work either - Add the masses of the quarks.
  4. May 17, 2006 #3
    Charge values are: u = +2/3; d = -1/3
    2 up + 1 down = +1
    add the charge values.
    Last edited: May 17, 2006
  5. May 17, 2006 #4
    sry i meant 2 " up" quarks and 1 " down" quark. does it work now?
  6. May 17, 2006 #5
    another thing i understand is that quarks isn't actually IN the proton itself isn't? so how can we say that to proton CONTAIN quarks IN it
  7. May 21, 2006 #6


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    what is quarks made of?
  8. May 21, 2006 #7


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    The proton is made up of quarks.

    There aren't quarks "inside" of a proton because that implies there exists a structure called a proton independently of quarks.

    Edit: Well I guess there are also gluons.
    Last edited: May 21, 2006
  9. May 21, 2006 #8
    Summing the masses wouldn't give you any useful information for finding the number of quarks in a proton or neutron, without a lot of extra information. The sum of the quark masses is only a small percentage of the mass of a proton.

  10. May 22, 2006 #9
    I had this feeling that my teacher was wrong. :grumpy: I should've checked what he said, though. :redface: I stand corrected...Thanks. :smile:
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