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Homework Help: Calculating number of free electrons in metals

  1. Feb 21, 2016 #1
    Hello everyone, I need your help on a question. The question is "calculate the number of free electrons per cubic centimeter (and per atom)for sodium from resistance data(relaxation time= 3.1Exp-14s)
  2. jcsd
  3. Feb 21, 2016 #2
    Just use the formula for resisitvity. Probably you are using the Drude model.
    And you need to look up the value of resistivity.
    And better post this in the homework section.
  4. Feb 21, 2016 #3
    Yea I was using the drude model. I know the value of resistivity of sodium to be 4.2Exp-6
  5. Feb 21, 2016 #4
    Then what is your problem?
    Some units won't hurt.
  6. Feb 21, 2016 #5
    I was able to solve the 1st part but he second part (per atom) kind of eludes me
  7. Feb 22, 2016 #6
    Oh, you can find the number of atoms per cubic cm from density and atomic mass.
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