Geometrical optics
Describing light propagation in terms of rays.
Ray - idealized geometrical model of light.
Law of refraction possible to use for reflective surfaces, curved surfaces can be modeled by ray tracing.
Shell's law can show deflection of a light ray while refraction.
Lenses - devices which produces converging or diverging light rays during refraction. In general two types: convex and concave lenses.
Focal point can be modeled by lensmaker's equation, prediction of how images can be produced by lens formula.
Reflectivity between two materials possible to calc by Fresnel equations.