A fish is at a depth h below the surface of water $\left(\mathrm{\mu }=\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.\right)$ and a bird is at a height of 2m above the surface of water. The bird and fish are on the same vertical line. If the apparent depth of the fish as viewed by the bird is same as the apparent height of the bird as viewed by the fish, then value of h is