Relationship between refractive index and critical angle:
That is, the refractive index of the rare medium relative to the condensed medium is equal to = 1 / critical angle.
The refractive index of a medium is lowest for red color and highest for the purple color, so the critical angle value is highest for red color and lowest for purple color.
Reversibility of light rays:
Some practical examples of refraction of light:
1:Bent or broken look of a pencil placed in water on the surface:
2: Twinkling of stars at night in the sky:
3:Looking less than it’s the actual depth of the pond :
4:Higher appearance of the plane, the sun, stars, and the sky than actual:
5:Visibility of the sun even below the horizon at sunrise and sunset: