refraksjonstal

Refraksjonstal, often translated as refractive index, is a dimensionless number that describes how light propagates through a medium. It is defined as the ratio of the speed of light in a vacuum to the speed of light in that medium. The symbol commonly used for refractive index is 'n'. A higher refractive index indicates that light travels slower in that medium, and therefore, it bends or refracts more when passing from one medium to another.

The phenomenon of refraction, and thus the concept of refractive index, is crucial in understanding how lenses, prisms, and optical fibers work. When light enters a medium with a different refractive index at an angle, its speed changes, causing it to change direction. The amount of bending is governed by Snell's Law, which directly incorporates the refractive indices of the two media involved and the angle of incidence.

Different materials have different refractive indices. For instance, air has a refractive index very close to 1 (approximately 1.00029), while water has a refractive index of about 1.33, and glass typically ranges from 1.5 to 1.7. Diamond has a significantly higher refractive index of around 2.42, which contributes to its brilliance and sparkle. The refractive index of a material can also vary slightly with the wavelength of light, a phenomenon known as dispersion, which is responsible for separating white light into its constituent colors, as seen in a rainbow.