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

C

Explanation

`n_(2) gt n_(1) `
`i_(c ) = sin^(-1) ((1)/(n_(21)) = sin^(-1) ((n_(1))/(n_(2)))`
`rArr " " i_(c ) = sin^(-1) ((v_(2))/(v_(1))) = sin^(-1) ( (1.5 xx 10^(8))/(2 xx 10^(8)) )`
`rArr " " i_(c ) = sin^(-1) ((3)/(4))`
Incidence angle (I) `gt i_(C)`
i`ge sin^(-1) ((3)/(4))`