- #1

pinkfishegg

- 57

- 3

## Homework Statement

Use the Biot-Savart Law to find the magnetic field strength at the center of the semicircle in fig 35.53

## Homework Equations

B

_{current}=(μ/4π)*(IΔsXr

^{^})/r

^{2}

B

_{wire}=μI/2πd

## The Attempt at a Solution

The solution from the back of the book is

B=μI/4πd

It looks like they just added the two wires together and the the B-field of the loop in the middle is zero. I don't understand what the cross product would give you zero though. The example that derived the B-field of a wire put a point on the y-axis and used that to find R and determine the cross-product. Why would that lead to a cross product of zero for the arc?