A beam of white light is incident on glass air interface from glass to air such that green light just suffers total internal reflection. The colours of the light which will come out to air are

Condition for light to transmit is sin $C<1/\mu and{\mu }_V>{\mu }_g>{\mu }_r$

Total internal reflection will occur for those wavelengths of light for which the critical angle is smaller than that of green light. Yellow, orange, and red, for example, won't experience total internal reflection.