Anti-radiation missile as the longer the radar is off (and assuming it never turns back on), the more error is introduced into the missile's course. The ALARM even has an added loiter mode, with a built in parachute, enabling it to descend slowly until the radar lights up, when the rocket motor will re-ignite. Even a temporary shut down of the enemy's missile guidance radar can be of a great advantage to friendly aircraft during battle. The DRDO Anti-Radiation Missile is under development by India. The MAR-1 is under development by Brazil. Several surface-to-surface missiles, like the P-700 Granit, P-500 Bazalt, MM40
Refraction different speed. The amount of ray bending is dependent on the amount of difference between sound speeds, that is, the variation in temperature, salinity, and pressure of the water. Similar acoustics effects are also found in the Earth's atmosphere. The phenomenon of refraction of sound in the atmosphere has been known for centuries; however, beginning in the early 1970s, widespread analysis of this effect came into vogue through the designing of urban highways and noise barriers to address the meteorological effects of bending of sound rays in the lower atmosphere. Refraction In physics refraction is the change in direction of