Given,

The magnitude of the magnetic field, $B=0.1 \mathrm{T}$

The radius of disk, $R=0.1 \mathrm{m}$

Rotational speed, $\mathrm{\omega }=2\mathrm{\pi }\times \text{revolution per second}=20\mathrm{\pi } \mathrm{rad} {\mathrm{s}}^{-1}$

Consider a small radial segment $\mathrm{d}r$ at distance $r$ from the center.

The emf generated in this small elemental rod will be,

$\mathrm{d}E=vBd\mathrm{r}$, here $v$ is the velocity of rod.

We know at any radial distance $r$, linear velocity will be,

$v=r\omega$

$\Rightarrow \mathrm{d}E=\omega Brd\mathrm{r}$

Since all these differential rods are connected in series, so net emf will be,

$$\begin{gathered} \int \mathrm{d}E={\int }_0^R\mathrm{\omega }Br\mathrm{dr} \\ \Rightarrow E=\frac{\mathrm{\omega }B{R}^2}{2} \\ \Rightarrow E=\frac{20\mathrm{\pi }\times 0.1\times {\left(0.1\right)}^2}{2}=\mathrm{\pi }\times {10}^{-2} \mathrm{V} \end{gathered}$$