Regular reflection, diffuse reflection, refraction and absorption are optical phenomena studied by Physics.
In physics, we study these phenomena separately to facilitate the understanding of these contents, which are quite complex.
When a beam of parallel rays strikes a polished surface, propagating in medium 1, it returns to medium (1) without losing parallelism.
The beam of parallel rays coming from the medium (1) strikes the separation surface with the medium (2) losing its parallelism and being scattered in all directions.
Light, coming from the medium (1), crosses the separation surface between the two media and starts to propagate in the medium (2). middle (1).
Refraction of Light
The light coming from the medium (1) reaches the medium (2), however, it does not return to the initial propagation medium and does not start to propagate in the medium (2). This light, because it is energy, is absorbed by the surface.