Question $2($Mandatory$)(20$ points$)$

A point source light at the bottom of the shallow end of a neighborhood swimming pool is $1\mathrm{.}40$ meters below the surface of the water. When the water surface is perfectly still, what is the diameter of the circle of light that emerges? The index of refraction of water is $1\mathrm{.}33,$ and $1\mathrm{.}00$ for air.

$$