This work presents a new formulation of the laws of reflection of light, and it is shown the equivalence between the new and the classic formulations. The proposed formulation has a significant educational value, as it allows drawing analogies between the phenomena of light reflection and elastic collisions, which are very well known by students. The new developed statement of the law of reflection allows the resolution of traditional problems of geometrical optics, and in some cases the solution is much simpler and more intuitive than that obtained using the traditional statement of the laws of reflection. As an example, this formulation is applied for the resolution of the classic reflection problem of the three plane mirrors forming a trirectangular trihedron, also known as corner reflector.
Slowdown and Heating of Interstellar Neutral Helium by Elastic Collisions beyond the Heliopause
