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Staple Gun
Oct7-08, 12:41 PM
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.

G01
Oct7-08, 12:49 PM
Ohm's Law comes in two forms. The form more common to intro physics is:

V=IR

The other form is the following:

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

Can you use these equations to answer the questions?

Staple Gun
Oct7-08, 01:02 PM
Thanks GO1!! Thats exactly what i was looking for. I've got the answers now :)