Question

A fish lies at the bottom of a 4 m deep water lake. A bird flies 6 m above the water surface and refractive index of water is 4/3. Then calculate the distance between fish and the image of bird. [2 Marks]

Answer 1

If $y^{\prime }$ is the apparent height of the bird above water,
$\frac{y^{\prime }}{6}=\frac{{\mu }_w}{{\mu }_a}=\frac{4}{3}$
$\Rightarrow y^{\prime }=8m$ [1 Mark]
So distance between the fish and the image of bird $=4+8=12m$ [1 Mark]