The speed of light in media `M_1` and `M_2` are `1.5 xx 10^8 m//s and 2.0 xx 10^8 m//s` respectively. A ray of light enters from medium `M_1` to `M_2` at an incidence angle `i`. If the ray suffers total internal reflection, the value of `i` is.

Options

A. Equal to `sin^(-1)(2/3)`
B. Equal to or less than `sin^(-1)(3/5)`
C. Equal to or greater than `sin^(-1)(3/4)`
D. Less than `sin^(-1)(2/3)`

Answer

3

Explanation

`mu_(1) = C/v_(1) = (3xx10^(8))/(1.5xx10^(8))` = 2
`mu_(2) = C/v_(2) = (3xx10^(8))/(2xx10^(8)) = 3/2`
Now sinC = `mu_(2)/mu_(1)` for total internal reflectiion
sini`gt=` sinC
`:. `sini`gt= mu_(2)/mu_(1)gt= (3//2)/2` or `I gt= sin^(-1) 3/4`