1. The problem statement, all variables and given/known data A wire carries a current of 3 A in the downward direction. What is the magnetic field 2.0 cm away from the wire? 2. Relevant equations ∫B·dl = µ0I 3. The attempt at a solution So I pick a circle with radius 2.0 cm to go around the wire, and get B∫dl = µ0(3 A) ∫dl evaluates to 2pi(0.02 m). So B = [µ0(3 A) ] / 2*pi*0.02 m?