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 medicine, particularly optometry, ophthalmology and orthoptics, "refraction" (also known as "refractometry") is a clinical test in which a phoropter may be used by the appropriate eye care professional to determine the eye's refractive error and the best corrective lenses to be prescribed. A series of test lenses in graded optical powers or focal lengths are presented to determine which provides the sharpest, clearest vision. In underwater acoustics, refraction is the bending or curving of a sound ray that results when the ray passes through a sound speed gradient from a region of one sound speed to a region of a