Question

What happens when a ray of light travels from a denser to a rarer medium? Give one consequence of this phenomenon. What happens when the angle of incidence is gradually increased?

Answer 1

The ray will bend towards the normal.
Because of this phenomenon the bottom of a tank appears to be raised.
As the angle of incidence is increased, at a particular angle of incidence called the critical angle, the angle of refraction will be 90 degree. After this, any increase in the incident angle will result in the phenomenon of Total Internal Reflection.