Linked from
The 14 pages that link to Fresnel equations, each with the reason it gives.
Refractive indexRelated: They show how refractive indices set reflected and transmitted amplitudes.
Specular reflectionRelated: They determine reflected energy and polarization at the surface.
Thin-film interferenceRelated: They determine the amplitude and phase of each boundary reflection.
Optical windowRelated: They predict reflection from the window’s front and back surfaces.
Anti-reflective coatingRelated: They predict how much light each coating boundary reflects.