A second-order change in the quantity that governs this phenomenon due to an electric field is called the Kerr effect.  A "double" form of this phenomenon creates two rays of different polarizations and is called birefringence. This phenomenon is described by a law that relates the ratio of the sines of the angles involved 
A second-order change in the quantity that governs this phenomenon due to an electric field is called the Kerr effect.  A "double" form of this phenomenon creates two rays of different polarizations and is called birefringence. This phenomenon is described by a law that relates the ratio of the sines of the angles involved to the reciprocal ratio of the refractive indices; that law is named for Snell. For 10 points, name this phenomenon, in which the path of a beam of light is bent as it enters a new medium.
A second-order change in the quantity that governs this phenomenon due to an electric field is called the Kerr effect.  
{refraction}