What will be the diameter of your coil?

[j88k]

Homework Statement

You have a 1.10-m-long copper wire. You want to make an N-turn current loop that generates a 0.800 mT magnetic field at the center when the current is 1.50 A. You must use the entire wire.

What will be the diameter of your coil?

Homework Equations

B = (mu_0)(n)(i)/(2r)

2(pi)(r)(n) = 1.1 ?

The Attempt at a Solution

0.8 * 10^-3 = 4(pi)*(10^-7)n(1.5)/2r

find n/r from this then:

nr = 1.1/2(pi)

combine the two you get r^2 = ...

I'm not sure if I am going right here although I'm quite positive.. Need help on the calculations.

 

[j88k]

ok.. if the question was this: You have a 1.0-m-long copper wire. You want to make an N-turn current loop that generates a 1.0 mT magnetic field at the center when the current is 1.0 A. You must use the entire wire.

the answer would be:

http://img10.imageshack.us/img10/8501/picture3vwq.png

now please help me find the answer that corresponds to my values.

 

[j88k]

anyone?