Figure, a light ray is incident on the lower medium boundary at an angle if `45^(@)` with the normal. Which of the following statement `is//are` true?

Options

A. If `mu_(2) gt sqrt(2)` then angle of deviation is `45^(@)`
B. If `mu_(2) lt sqrt(2)` then angle of deviation is `90^(@)`
C. If `mu_(2) lt sqrt(2)` then angle of deviation is `135^(@)`
D. If `mu_(2) gt sqrt(2)` then angle of deviation is `0^(@)`

Answer

A, B

Explanation

For `mu_(2) gt sqrt(2)` (TIR will not take place)
`2sin45^(@)=mu_(2)sinr`
`mu_(2) sin r=sqrt(2) sin e`
`e=90^(@)`
Hence deviation is `45^(@)`
`mu_(2) lt sqrt(2)` TIR will take place deviation is `90^(@)`