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Homework Help: What diameter wire should be used for particular resistance?

  1. Oct 3, 2009 #1
    1. The problem statement, all variables and given/known data

    If 49 m of nichrome wire is to have a resistance of 16.0 ohms at 20 degrees Celcius, what diameter wire should be used?

    2. Relevant equations

    R = [tex]\rho[/tex] x L / A

    A = [tex]\Pi[/tex] d^2 / 4

    3. The attempt at a solution

    well i know what i'm looking for, that is d (diameter)

    and d = [tex]\sqrt{}[/tex](4[tex]\rho[/tex]L/[tex]\Pi[/tex]R)

    I don't know what the value of [tex]\rho[/tex] is.

    I know it is supposed to be the resistivity of the material, at a certain temperature, but I have no idea how to include it in the equation.

    Please Help!
  2. jcsd
  3. Oct 3, 2009 #2


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