Question

A pond of depth 20 cm is filled with water of refractive index `4//3`. Calculate apparent depth of the tank when viewed normally.

Answer 1

Here, real depth of pond, `x = 20 cm`,
refractive index of water, `.^(a)n_(w) = 4/3`
apparent depth, `y = ?`
As `.^(a)n_(w) = x/y`,
`y = x/(.^(a)n_(w)) = 20/(4//3) = 20xx(3)/(4) = 15 cm`