1. The problem statement, all variables and given/known data A long pair of wires serves to conduct I = 25.2 A of dc current to and from an instrument. If the wires are of negligible diameter but are d = 2.92 mm apart, what is the magnitude |B| of the magnetic field a distance L = 9.5 cm from their midpoint, in their plane? What is the ratio |B|/|BEarth|, where |BEarth| = 5.0 × 10-5 is the magnetic field of the Earth. 2. Relevant equations B = mu0*I/2pi*r 3. The attempt at a solution I know that to find B it's just a matter of plugging in the current into the equation above and the r I am not sure about. Someone please clarify this for me?