The law of reflection states that when a light ray hits a surface, the angle at which it arrives (angle of incidence) equals the angle at which it leaves (angle of reflection). This fundamental principle applies to all mirrors, including both plane and spherical mirrors, because reflection is a surface phenomenon. It does not apply to lenses, as lenses operate on the principle of refraction, where light bends as it passes through a material.

Final answer: plane and spherical mirrors.