Anti-radiation missile Anti-radiation missile An anti-radiation missile (ARM) is a missile designed to detect and home in on an enemy radio emission source. Typically, these are designed for use against an enemy radar, although jammers and even radios used for communications can also be targeted in this manner. Most ARM designs to date have been intended for use against ground-based radars. Commonly carried by specialist aircraft in the Suppression of Enemy Air Defenses (SEAD) role (known to the United States Air Force as "Wild Weasels"), the primary purpose of this type of missile is to degrade enemy air defenses in the first
Refraction of incidence "θ" and angle of refraction "θ" is equal to the ratio of phase velocities ("v" / "v") in the two media, or equivalently, to the indices of refraction ("n" / "n") of the two media. Optical prisms and lenses utilize refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelength of light, and thus the angle of the refraction also varies correspondingly. This is called dispersion and causes prisms and rainbows to divide white light into its constituent spectral colors. Consider a wave going from one material to another where