physics
posted by Anonymous .
Two parallel wires in a horizontal plane carry currents I1 and I2 to the right. The wires each have a length L and are separated by a distance d. calculate the following where: I1 = 10A, I2 = 20A, d = 5mm, and L = 2m. What are the magnitude and direction of the Bfield of wire 1 at the location of wire 2?

You don't have to know what I2 is for that.
You want the formula for the field at a dstance r = 0.005 m from wire 1. You can assume it has infinite length when you are that close to it compared to the length.
Use Ampere's law and the right hand rule for the B field magnitude and direction.
http://hyperphysics.phyastr.gsu.edu/hbase/magnetic/magcur.html
B = uo*I/(2*pi*r) (in Tesla)