# Calculating current in parallel wire

1. Jul 16, 2011

### djaziria

1. The problem statement, all variables and given/known data

A vertical straight wire carrying an upward 14.9A current exerts an attractive force per unit length of 8.50×10-4N/m on a second parallel wire 6.20cm away. What is the magnitude of the current that flows in the second wire?

2. Relevant equations

I2=2pir*F/I1*4pi e-7

3. The attempt at a solution

I2=2pi(.062)*8.5e-4/14.9*4pi e-7
I2=2.7926e-11

I keep getting ridiculous numbers and I can't figure out what I'm doing wrong...help?!

2. Jul 16, 2011

### amy andrews

I think you got your equation slightly off.
Starting with F/$\Delta$L=$\mu$0I1I2/2pi*r, I ended up with
I2=(F/$\Delta$L)(2pi*r/$\mu$0I1).

3. Jul 17, 2011

### Antiphon

Check your own arithmetic. The exponents indicate you screwed up the division.

Do the basic checks before running for help.