Homework Help: Magnetic Force away from Long Pair of Wires

1. Feb 8, 2010

Tjvelcro

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

A long pair of wires conducts 20.2 (amps) od dc current to, and from, an instrument. The wires are 23mm apart, what is the magnetic field 9.7cm from their midpoint in thier plane?

2. Relevant equations

B=(µo/2pi)*(I/d)

3. The attempt at a solution

µo = 4pix10^-7
I = 20.2 amps
d = ??? = distance to the wire

I first need to find d for one wire then d for the other so I can combine them to get the total Magnetic force at the point 9.7cm away from the wires.

I have the answer from the back of the book and it says 1.00x10^-5 but I don't know how to get it.

First I drew a diagram

___________________ Wire 1
23mm between
___________________ Wire 2

. Point 9.7 cm from the midpoint of the plane.

Then I used the formula twice, once for each wire but I dont get the right answer

Thanks

Tjvelcro

2. Feb 8, 2010

Tjvelcro

Nevermind, I was not using my calculator correctly. Brackets are very helpful :p