# Electric Field in a Wire (Concepts)

1. Oct 7, 2008

### Staple Gun

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. Oct 7, 2008

### G01

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?

3. Oct 7, 2008

### Staple Gun

Thanks GO1!! Thats exactly what i was looking for. I've got the answers now :)