index of refraction


noun Optics.

a number indicating the speed of light in a given medium as either the ratio of the speed of light in a vacuum to that in the given medium (absolute index of refraction) or the ratio of the speed of light in a specified medium to that in the given medium (relative index of refraction). Symbol: n
Also called index, refractive index.

Origin of index of refraction

First recorded in 1820–30

Example sentences from the Web for index of refraction

  • He'd gotten an index-of-refraction reading on crystals too small to be seen except through a microscope.

    The Hate Disease |William Fitzgerald Jenkins

British Dictionary definitions for index of refraction

index of refraction

noun

another name for refractive index

Scientific definitions for index of refraction

index of refraction

A measure of the extent to which a substance slows down light waves passing through it. The index of refraction of a substance is equal to the ratio of the velocity of light in a vacuum to its speed in that substance. Its value determines the extent to which light is refracted when entering or leaving the substance.