Fields generated by a rotating disk

lailola

Homework Statement

We have an uniformly charged disk with total charge q, which is rotating around its axis with constant angular velocity w. Calculate electric and magnetic field in the axis and in the rotation plane. Calculate the radiated power in one cicle.

Biot-Savart law.
v=wr

The Attempt at a Solution

I only know how to calculate the magnetic field in the center, using directly the biot-savart law:

$d\vec{B}=\frac{\mu}{4\pi}dq\frac{\vec{v}×\hat{r}}{r^2}$
$B=∫_{0}^{a} \frac{\mu}{4\pi}\sigma 2\pi r dr\frac{wr}{r^2}=\frac{\mu w \sigma a}{2}=\frac{\mu w q}{2\pi a}$

How can I calculate the rest?

Thank you.

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