The slab of a material of refractive index ${\mu }_2=2$ shown in figure has a curved surface $\mathrm{APB}$ of radius of curvature $10 \mathrm{cm}$ . On the left of $\mathrm{APB}$is air .  An object $\mathrm{O}$ is placed at a distance of $15 \mathrm{cm}$ from the pole $\mathrm{P}$ as shown. The distance of the final image of $\mathrm{O}$ from $\mathrm{P}$, as viewed normally from the left is ….. cm.