Refraction of light is the way in which light ‘bends’ when it passes from one medium to another.
LAWS AND PRINCIPLES
Laws of Refraction Law 1 The incident ray, normal and the refracted ray are all in the same plane.
Normal at the point of incidence
i r Glass Fig 13.2: Laws of refraction, Law 2 Air Fig 13.1: Laws of refraction, Law 1
Law 2 The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for two given media.
The second law is called Snell’s law. SNELL’S LAW
sin i sin r n
n refractive index between the two media, i angle of incidence, r angle of refraction
Refractive Index of a Medium REFRACTIVE INDEX OF A MEDIUM
The refractive index (n) of a medium is the ratio of sine i to sine r when the light travels from a vacuum to that medium.
WILLEBRORD SNELL, 1580–1626 (DUTCH) He discovered the law of refraction, now called Snell’s law, calculated the radius of the Earth and improved the approximation of (to 7 decimal places). Snell did not publish his law when he discovered it in 1621; Christiaan Huygens published it in 1701, but Snell is still given credit for it.
