Anti-radiation missile of radiation and explode when they got near it. SAM operators learned to turn their radar off when an ARM was fired at them, then turn it back on later, greatly reducing the missile's effectiveness. This led to the development of more advanced ARMs such as the AGM-78 Standard ARM and AGM-88 HARM missiles, which have inertial guidance systems (INS) built-in. This allows them to remember the radar's direction if it is turned off and continue to fly towards it. ARMs are less likely to hit the radar if the radar is turned off shortly after the missile is launched,
Refraction Refraction In physics refraction is the change in direction of a wave passing from one medium to another or from a gradual change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle