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Electric Field HW Help

  1. Mar 8, 2012 #1
    1. The problem statement, all variables and given/known data
    A copper wire 90 cm long a 1.00 mm in diameter has a mass of 6.35g.

    A) Find the number of electrons in the wire. (Copper has an atomic number of 29; that is there are 29 protons in the copper atom. Copper's atomic mass is 63.5)

    B) There is one free electron per atom in copper. Find the number of free electrons in the wire.

    2. Relevant equations

    I'm not sure... but these might be helpful. mass of electron= 9.11x10^-31kg.F=k(q x q/r^2)

    3. The attempt at a solution

    I tried plugging into this equation but it does not work.
  2. jcsd
  3. Mar 9, 2012 #2
    atomic mass is related to the kilograms. you have the mass of the wire, so using this find the no of atoms in the wire . no of atoms in the wire is mass of wire over atomic mass.
    careful about the units
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