1. The problem statement, all variables and given/known data You have 12m of 0.50mm diameter copper wire and a power supply capable of passing 17A through the wire. What magnetic field strength would you obtain inside a 2.0cm diameter solenoid with the wire spaced as closely as possible? 2. Relevant equations B=u0nI 3. The attempt at a solution I found the number of loops by D=.002+2*1*10-3m (diametre plus 2 radi of wire)??? then n=12/circumfrence =173.6turns (C=pi*D then I subbed all the values and got 0.0037T which is wrong all help appreciated - I think my problem is in calculating the number of turns??