Maximum value of angle of refraction

Question

So I have been learning geometrical optics and I have a few questions:

1. Is critical angle the maximum value of angle of refraction when light travels from a rarer medium to a denser medium?

2. Is $90^\circ$ the maximum angle of refraction when light travels from a denser medium to a rarer medium?[provided no total internal reflection occurs]

Answer 1

Answers:-

1. For light travelling from a denser medium to a rarer medium, critical angle is defined as the angle of incidence of the incident ray for which the refracted ray travels along the interface between the two media (i.e. angle of refraction is $90^\circ$). This term is not valid for light rays travelling from rarer medium to denser medium as it is not possible for angle of refraction to be $90^\circ$ in such a case.

Where $\theta_c$ is the critical angle for the given pair of media.

2. In a way, yes, we can say that the maximum angle of refraction is $90^\circ$ for light travelling from denser medium to rarer medium, if total internal reflection is not considered, and in that case, the angle of incidence must be equal to the critical angle ($\theta_c$). If angle of incidence is greater than the critical angle, then total internal reflection takes place and no refraction occurs.

Hope it helps.