# Pie shaped loop of radius a carraying a current I

1. Jun 16, 2005

### aimee

I have been trying to do this for hours...

I know I'm supposed to use the Biot-savart Law: dH = IdLsin(theta)/4pir^2

Determine the magnetic field at the apex of the pie-shaped loop shown below. Ignore the contributions of the field due to current int he small arcs near 0.

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2. Jun 16, 2005

### Staff: Mentor

What have you done so far?

If you write the Biot-Savart law like this, you may see a few shortcuts:
$$d\vec{B} = \frac{\mu_0 I}{4 \pi} \frac{d\vec{L} \times \hat{r}}{r^2}$$

What can you conclude about the contribution to the field due to the current in the straight wire pieces? What about the curved piece?