# Biot-Savard law

1. Oct 16, 2008

### lemaire

1. The problem statement, all variables and given/known data

A single piece of wire is bent so that it includes a circular loop of radius a. A current I flows in the direction of the x axis . Find an expression for the magnetic field at the center of the loop.
2. Relevant equations

3. The attempt at a solution
This is a problem involving the integrated Biot-Savard law

2. Oct 16, 2008

### Hootenanny

Staff Emeritus
You are correct, the Biot-Savart law is the way to go.

3. Oct 16, 2008

### lemaire

well i can't find the right expression.

4. Oct 16, 2008

### Hootenanny

Staff Emeritus
What have you tried?

5. Oct 16, 2008

### lemaire

this is what i have: (mu_0IL)/(4pia2) with a being the radius and mu_0 being the permeability constant

6. Oct 16, 2008

### Hootenanny

Staff Emeritus
Looks correct to me. However it can be simplified by noting that $L = 2\pi a$.

7. Oct 16, 2008

### lemaire

well i am using a web software and the response you and i agreed on is not the right one. In the picture, the current I comes from the left in the x axis goes in a circular motion and continues in the x axis again.