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Homework Help: Electric Field in a Wire (Concepts)

  1. Oct 7, 2008 #1
    1. The problem statement, all variables and given/known data

    A) [Directly proportional/Inversely proportional] The electric field inside the wire is ... to resistivity of the material the wire made of.

    B) [Directly proportional/Inversely proportional] The electric field inside the wire is ... to the current passing through the wire.

    2. Relevant equations
    This is my problem, I can't seem to find any equations that relate electric field to the resistivity or current in the wire.

    3. The attempt at a solution
    My guess is that A is inversely proportional, and B is directly proportional but its just a guess.
     
  2. jcsd
  3. Oct 7, 2008 #2

    G01

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    Homework Helper
    Gold Member

    Ohm's Law comes in two forms. The form more common to intro physics is:

    [tex]V=IR[/tex]

    The other form is the following:

    [tex]J=\sigma E[/tex] where J is the current density and sigma is the conductivity (inverse of resistivity).

    Can you use these equations to answer the questions?
     
  4. Oct 7, 2008 #3
    Thanks GO1!! Thats exactly what i was looking for. I've got the answers now :)
     
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