Physics
posted by Anab .
A swimming pool filled with water to its edge, the depth of the water is 2m and an electric lamp is placed at a distance equals 8m from the edge of the pool over a column its height 6m. Calculate the length of nonapparent part from the pool bottom with the light does not reach to it, given the refractive index of water is 4?3.

I believe that the refractive index of water is n=1.3
Incidence angle α.
sin α =8/sqrt(8²+6)=0.8
sinα/sinβ=n =>
sinβ= sinα/n =0.8/1.3=0.61 =>β= 38°
x=h•tan β=2•tan38°=1.56 m