Question

An under water swimmer is at a depth of 12 m below the surface of water. A bird is at a height of 18 m from the surface of water, directly above his eyes. For the swimmer the bird appears to be at a distance ______ from the surface of water. (Refractive Index of water = 4/3 )
Answer : 24cm

Answer 1

Using formula

$$\frac{L'}{L}=n$$ $$n=4/3; L=18 (m)$$ $$L'=n\cdot L= 24 (m)$$