(i) Why is the ratio of the velocities of light of wavelengths 4000 Å and 8000 Å in vacuum 1 : 1 ?

(ii) Which of the above wavelengths has a higher frequency?

State the position of the object in front of a converging lens if:

(i) It produces a real and same size image of the object.

(ii) It is used as a magnifying lens.

(i) State the relation between the critical angle and the absolute refractive index of a medium.

(ii) Which colour of light has a higher critical angle? Red light or Green light.