The refractive index of water is 4 / 3 and that of glass is 5/3. What will be the critical angle for the ray of light entering water from the glass

Options

A. `sin^(-1) (4//5)`
B. `sin^(-1)(5//4)`
C. `sin^(-1) (1//2)`
D. `sin^(-1) (2//1)`

Answer

A

Explanation

`._(w)mu_(g) = (mu_(g))/(mu_(w)) = (5//3)/(4//3) = (5)/(4)`
Now, `._(w)mu_(g) = (1)/(sin c)`
`:. sin c = (1)/(._(w)mu_(g)) = (4)/(5) :. c = sin^(-1) (4//5)`