# Resistivity and Ohm's Law question

1. Jul 28, 2012

### Vickyvicksss

1. The problem statement, all variables and given/known data
A long wire connected to the terminals of a 12V battery has 6.4 x 1019 electrons passing a cross section of wire each second. calculate it's resistance.

2. Relevant equations
q = ne
q = IE
R=ρ L/A

3. The attempt at a solution
V= 12v
n= 6.4 x 1019 electrons
R=?

First I used the number of electrons to find my charge (q)
q = ne
q = (6.4 x 1019) ( 9 x 10-31)
q = 5.76 x 10 -11

Then calculating my current
I= Q/T
Im assuming T is 1s, because it says "passing a cross section of wire each second"
I = 5.76 x 10 -11/ 1
I= 5.76 x 10 -11

Then i calculated my resistance
R= V/R
R= 12/5.76 x 10 -11
R= 2.0 x 1011

What am i doing wrong? D:

2. Jul 28, 2012

### rock.freak667

The charge of an electron is e=1.6(10-19) C.

3. Jul 28, 2012

### Simon Bridge

... that would be the electron mass.

e=1.60217646×10-19 Coulombs

4. Jul 28, 2012

### Vickyvicksss

LOL! CRAP! i knew that~ :) Thank you :3 I was going insane for a bit.

5. Jul 29, 2012

### Simon Bridge

Happens to the best of us :-)