1. The problem statement, all variables and given/known data A long straight wire lies on a horizontal table and carries a current of 1.09 μA. A proton moves parallel to the wire (opposite the current) with a constant velocity of 12200 m/s at a distance d above the wire. The acceleration of gravity is 9.8 m/s2. Determine this distance of d. You may ignore the magnetic field due to the Earth. Answer in units of cm. 2. Relevant equations F = mg F = qvB B = (mu)* I / (2pi*r) 3. The attempt at a solution I set mg = qvB and I solved for B. After I found B, I plugged B into the equation B = (mu)* I / (2pi*r) to find r which I assume to be the distance that the question is asking for. Here are the numbers I worked with: (1.67e-27 kg) (9.81 m/s^2) = (1.602e-19 C)(12200 m/s) * (B) B = 8.38e-12 To find r, 8.38 e-12 = [(4pi e-7)*(1.09e-6)] / [2pi * r] I solved for r and found it to be 25.67 cm but this isn't the right answer. Could someone tell me what I did wrong?