The same two conditions that are necessary for bending the path of the line of students are also necessary for bending the direction of a light ray. Light refracts at a boundary because of a change in speed. There is a distinct cause-effect relationship. read more
The real reason behind refraction is the dependency of Wavelength over the Refractive index of the medium. As the EM waves move from the denser medium to rarer medium, they tend to move away from the perpendicular of the medium boundary. read more
The refraction of light at the interface of two optically different media can be explained in three different ways. Farmat’s principle of least time. According to this variational principle light travels between two points along that path for which time of travel is minimum( in fact extremum). read more
Refraction is merely one of several possible boundary behaviors by which a light wave could behave when it encounters a new medium or an obstacle in its path. The transmission of light across a boundary between two media is accompanied by a change in both the speed and wavelength of the wave. read more