1. The problem statement, all variables and given/known data A closed loop carries a current of 8.0 A in the counterclockwise direction. The radius of the outer arc is 0.6m and that of the inner arc is 0.40m. What is the magnetic field at P? 2. Relevant equations F = ILxB F = qV x B R = outer radius r = inner radius 3. The attempt at a solution ILxB = mV2/R I don't even know how to APPROACH this problem. Please help me. These equations above have too many unknowns to give me an answer and so I need more. I can find L but I can not find m and V in terms on knowns, and even still I think this is a horrible way of solving the problem. I would like to do a sum of forces but ∑F = ILxB + qvxB = ma doesn't exactly help because if I replace a with mv2/R I still have as many unknowns as before but this time I need q and v.