# Homework Help: Solenoid Magnetic Field wire spacing Help

1. Aug 6, 2010

### pat666

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??

2. Aug 6, 2010

### 6Stang7

The diameter of the wire will effect the pitch (loop density) of the coil, but not the total number of loops. I take it you have the answer to the problem?

Last edited: Aug 6, 2010
3. Aug 6, 2010

### pat666

Hey, its for an online mastering physics test - - - - using D as .02m I get .00408T but I didnt use the radius at all so I think it may be wrong???