Out of violet, blue, yellow and red, the critical angle would be the least for …………… light for a pair of media.

1. violet
2. blue 
3. blue 
4. yellow

A ray of white light is incident on the interface of glass and air as shown in the figure. At the given angle of incidence, green light suffers total internal reflection. The rays emerging out from glass to air contain :

1. yellow, orange and red colours
2. violet, indigo and blue colours
3. all colours
4. all colours except green

The critical angle for glass-air is 45° for the light of yellow colour. State whether it will be less than, equal to, or more than 45° for

(i) red light,

(ii) blue light ?

Which colour of light has higher critical angle ? Red light or green light.