# Concentric Arcs (Biot Savart)

1. Oct 15, 2007

### Winzer

1. The problem statement, all variables and given/known data
The closed loop shown in the figure below carries a current of 6.90 A in the counterclockwise direction. The radius of the outer arc is 65.0 cm, that of the inner arc is 41.0 cm. Find the magnitude of the magnetic field at point P if the angle 60 deg.

2. Relevant equations
Savart
$$db=\frac{uI dl x r}{4\pi r^3}$$
dl and r are vectors
x means cross product

3. The attempt at a solution
Basically integrate the outer wire, the inner wire and add them up right?

#### Attached Files:

• ###### ConcentricArcs.gif
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2. Oct 15, 2007

### Kurdt

Staff Emeritus
You will have to split the question into 4 parts to find the contribution of the 4 different sections. The cross product is useful here as it simplifies the different parts greatly.

3. Oct 15, 2007

### Winzer

I figured it out.