# Separation distance between wires - Magnetic fields

1. Jun 24, 2011

### SimonSays

1. The problem statement, all variables and given/known data
http://i.imgur.com/mgIkS.png
Two long parallel wires carry currents of 2.03 A and 8.83 A. The magnitude of the force per unit length acting on each wire is 4.49*10^5 N/m. Find the separation distance of the wires expressed in millimeters.

2. Relevant equations
I'm not entirely sure.

3. The attempt at a solution
I thought that I would need to use the formula:
http://latex.codecogs.com/gif.latex?F_{21}=(\mu_0*I_1*I_2*L )/(2\pi d)
I don't have L however, so how do I solve for d?

Last edited by a moderator: Apr 26, 2017
2. Jun 24, 2011

### rickz02

Actually you have the right formula, just understand the parameters involved and relate to the given problem.

Hint: "The magnitude of the force per unit length acting on each wire is 4.49*10^5 N/m."

3. Jun 24, 2011

### SimonSays

So are you suggesting that L=1?
Edit: I tried it with L=1 and it worked. Thanks!

Last edited: Jun 24, 2011
4. Jun 24, 2011

### rickz02

We'll you can say that, but I can also say L=2 and my F = 2.245x105 N/m.

What I want you to understand is that you don't need to know L as you are readily given with F/L.