$($a$)$

A small light fixture on the bottom of a swimming pool is $1\mathrm{.}48$ m below the surface. The light emerging from the still water forms a circle on the water surface. What is the diameter of this circle? $($Give your answer, in m$,$ to at least two decimal places.$)$

m

$($b$)$

What If$?$ If a $1\mathrm{.}78$ cm thick layer of oil

$($noil $=1\mathrm{.}35)$

is spread uniformly over the surface of the water, what is the diameter of the circle of light emerging from the swimming pool? $($Give your answer, in m$,$ to at least two decimal places.$)$

m