1. The problem statement, all variables and given/known data You have a 1.2-m-long copper wire. You want to make an N-turn current loop that generates a 0.60 mT magnetic field at the center when the current is 1.5 A. You must use the entire wire. 2. Relevant equations What will be the diameter of your coil? 3. The attempt at a solution I tried applying this formula d = sqrt ( (mu*L*I/pi*B)) and keep getting a really small number =0.000021 m What am I missing here??