Answer:
The diagram shows refraction and medium 1 is less dense than medium 2
Step-by-step explanation:
Refraction: The phenomenon of bending of light (moving towards or away from the normal), when it passes through different medium, is called Refraction. Here as can be seen when the light beam enters medium 2 from medium 1 it moves towards the normal (the dotted line perpendicular to the interface). This implies that medium 2 is denser than medium 1.