A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is `(4)/(3)` and the fish is 12 cm below the surface, the radius of this circle is cm is

Options

A. `36sqrt(5)`
B. `4sqrt(5)`
C. `36 sqrt(7)`
D. `26//sqrt(7)`

Answer

D

Explanation

`mu=(1)/(sintheta//2)impliessintheta//2=(4)/(3)`
`impliestan theta//2=(sqrt(7))/(3)`
Suppose the radius of this circle is `r`
`implies tan theta//2=(sqrt(7))/(3)=(r)/(h)`
`impliesr=(3h)/(sqrt(7))=(3xx12)/(sqrt(7))=(36)/(sqrt(7))m`