Question

A fish under water observes a freely falling stone in air . If the refractive index of water is ` 4/3`, what is the apparent acceleration of the stone as observed by the fish?

Answer 1

(i) Let `h_(1) and h_(1)^(1)` be the real and apparent height of the stoneat t = 0 s.
Let `h_(2) and h_(2)^(1)` be the real and apparent height of the stone at t = 1 s
The real distance travelled
` S = h_(1) - h_(2)`
Apparent distance travelled `h_(1)^(1) -h_(2)^(1) = S^(1)`
` mu = h_(1)/h_(1)^(1) ,h_(1)^(1) = h_(1)/mu and h_(2)^(1) = h_(2)/mu `
Use the relation ` s = ut + 1/2 at^(2)`
In both the cases, determine the apparent acceleration.
(ii) ` 13.1 ms^(-2)`