# Maxwell equation, magnnetic induction field question?

1. Jul 3, 2009

### coffeem

1. The problem statement, all variables and given/known data
Using "del cross B = u0J to deduce the magnetic induction field inside a long straight circular coil with 1000 turns per meter, carrying a current of 1A.

2. Relevant equations
Included in the question???

3. The attempt at a solution

I am struggling with this, it is the second (although self contained) part to another question. A tip would be enormously appretiated. Thanks

2. Jul 4, 2009

3. Jul 4, 2009

4. Jul 5, 2009

### coffeem

Hey thanks for replying. I have looked at that wiki article... and I am still too thick to work out what I have to do... Can someone please give me a more substantial hint??? Thanks

5. Jul 5, 2009

### Cyosis

There are a few things you should look at. First of symmetry can you tell me by using symmetry in which direction the B-field will point? Secondly can you find a contour such that you can apply Ampere's law easily?

Last edited: Jul 5, 2009
6. Jul 5, 2009

### coffeem

I know it will be going in circles around the coil. But I cant think of any contours... I am majorly missing something here.

7. Jul 6, 2009

### Cyosis

No the magnetic field will not be going in circles around the coil, how did you get to this answer?

For clarification. We are talking about a solenoid here right?