How do I solve numericals based on the refractive index?

Consider light travelling from air (1st medium) into water (2nd medium)

The constant, refractive index of the medium has also another meaning that it's the ratio of light speed in 1st medium (for example, air) to the light speed in 2nd medium (for example, water).

The angle i used is the angle of incidence at the interface (i.e. air water interface) measured from the normal to the interface, and the angle r is the angle of refraction measured also from the same normal.

Regards,

Team,

TopperLearning.