Question

Critical angle of light passing from glass to water is minimum for(a) red colour(b) green colour(c) yellow colour(d) violet colour

Answer 1

The answer will be (d) violet colour.

We know that refractive index μ is given as c/v where c is the velocity of light and v is the velocity of the respective colour in the medium. In refraction , the velocity of the red colour is maximum and that of the violet colour is minimum.