Focusing on a surface separating two propagating media, light suffers some or more of the following phenomena:
Light that strikes the surface and returns to the same medium regularly, ie the incident and reflected rays are parallel. It occurs on well-polished metal surfaces such as mirrors.
The light falling on the surface returns to the same medium irregularly, ie the incident rays are parallel, but the reflected ones are irregular. It occurs on rough surfaces, and is responsible for the visibility of objects.
Light strikes and crosses the surface, continuing to propagate in the other medium. Both rays (incident and refracted) are parallel, however, the refracted rays follow an inclined path in relation to the incident ones. Occurs when the surface separates two transparent media.
Light shines on the surface, however it is neither reflected nor refracted, being absorbed by the body and warming it. Occurs on dark surface bodies.
Light ray independence principle
When the rays of light intersect, they independently follow each other their path.
Principle of rectilinear propagation of light
The entire ray of light travels straight paths in transparent and homogeneous media.
To know more…
A way homogeneous is one that has the same characteristics in all volume elements.
A way isotope, or isotropicis where the speed of light propagation and other optical properties are independent of the direction in which the measurement is performed.
A way ordinary It is one that is both transparent, homogeneous and isotropic, such as the vacuum.