Homework Help: Where did I go wrong?

1. Nov 3, 2005

lw11011

A solenoid 77.1 cm long has 340 turns and a radius of 1.92 cm. If it carries a current of 1.85 A, find the magnetic field along the axis at its center. Answer in units of T.
I know the formula for the magnetic field is:
Magnetic field = permeability x turn density x current
I entered -
B=(1.25664x10^-6)(340/.771)(1.85)
Where did I go wrong?

2. Nov 3, 2005

ranger

I think you could use this

$$B = \frac{\mu_0.I.N}{l}$$

Last edited: Nov 3, 2005
3. Nov 3, 2005

cepheid

Staff Emeritus
:tongue2: He DID use that formula. You just reproduced what he said in words using symbols.

4. Nov 3, 2005

cepheid

Staff Emeritus
Looks ok so far. What makes you think that you went wrong? You didn't even post an answer, so it is not at all clear from your post what the problem is.

5. Nov 3, 2005

ranger

I stand corrected

6. Nov 3, 2005

lw11011

By using that formula I got the answer, 0.001 T. The computer program for our homework said the answer was wrong.