The refractive index is a measure of how much light bends when it passes from one medium to another. It indicates the speed at which light travels in a particular medium.
This law describes how light bends when it passes through different mediums based on their refractive indices.
Total Internal Reflection: This phenomenon occurs when light traveling in a denser medium tries to pass into a less dense medium but gets completely reflected back instead.
Critical Angle: The critical angle is the minimum angle of incidence at which total internal reflection occurs.