White light is incident on the interface of glass and air as shown in figure. If green ligth is just totally internally reflected then the emerging ray in air contains

Options

A. yellow,orange,red
B. violet,indigo,blue
C. all colours
D. all colours except green

Answer

A

Explanation

(c ) Criticle angle,
sin C=`1/µ`
`therefore` `C=sin^(-1)(1/µ)`
and as µ decreases with increase in `lambda` yellow, orange, red have higher wavelength than green, so µ will be less for these rays, and so criticle angle for these rays will be high, hence, if green is just totally internally reflected than yellow, orange and red rays will emerge out.