A fish rising vertically upward with a uniform velocity of 8 ms^-1, observes that a bird is diving vertically downward towards the fish with the…

A fish rising vertically upward with a uniform velocity of $\displaystyle 8 \mathrm{~ms}^{-1}$, observes that a bird is diving vertically downward towards the fish with the velocity of $\displaystyle 12 \mathrm{~ms}^{-1}$. If the refractive index of water is $\displaystyle \frac{4}{3}$, then the actual velocity of the diving bird to pick the fish, will be $\displaystyle \_\_\_\_$ $\displaystyle \mathrm{ms}^{-1}$.