1. The problem statement, all variables and given/known data A long straight wire lies along the z-axis and carries an 8A current in the +z direction. Find the magnetic field (magnitude and direction) produced at x = 0.4m, y = 0, z = .3m by a .7mm segment of wire centered at the origin. 2. Relevant equations B = u(0)I / 2piR 3. The attempt at a solution b = (4(pi)x10^-7) (8A) / (2pi (.7x10^-3) ==> 2.3 mT(tesla) I think that's right, but I'm not sure where the magnitude and direction with the vectors come in. I'm assuming you subtract vector 1 from origin vector to leave .4i + .3k. Then do you take the magnitude and multiply it by b? Thanks for any help.