Question:
An object $\mathrm{P}$ is focused by a microscope M. A glass slab of thickness $2.1 \mathrm{~cm}$ is introduced between $\mathrm{P}$ and $\mathrm{M}$. If the refractive index of the slab is $1.5$, by what distance should the microscope be shifted to focus the object again?
Solution:
