An air masked eye placed inside water refractive index, `mu` sees the outside world. The vertex angle of the cone in which the eye will see the outside world is

Options

A. `2sin^-1(1//mu)`
B. `2cos^-1(1//mu)`
C. `2sin^-1sqrt((mu^2-1))`
D. `2cos^-1sqrt((mu^2-1))`

Answer

A

Explanation

`musinC=1xxsin90^@`
`sinC=1//muimpliesC=sin^-1(1//mu)`
Vertex angle `=2C=2sin^-1(1//mu)`