index of refraction

American  

noun

Optics.

1. 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. n

---

index of refraction British  

noun

1. another name for refractive index

---

index of refraction Scientific  

1. 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.

---

Etymology

Origin of index of refraction

First recorded in 1820–30

Example Sentences

See Examples For:

index of refraction

The difference in index of refraction between the two materials defines the angle of that bending.

From Scientific American ● Nov. 18, 2022

Light entering a medium with a negative index of refraction, on the contrary, would bend backward, creating unexpected optical effects, such as a straw appearing to lean the wrong way.

From Scientific American ● Nov. 18, 2022

The angle of refraction depends on the index of refraction, as we saw in The Law of Refraction.

From Textbooks ● Aug. 12, 2015

In the situations shown in Figure 25.11, medium 2 has a greater index of refraction than medium 1.

From Textbooks ● Aug. 12, 2015

In the dry system n., representing the index of refraction of air is taken as 1.00; in the immersion systems n equals 1.33 for water, 1.52 for cedar oil and 1.66 for monobromnaphthalin.

From Microscopes and Accessory Apparatus Catalogue No. 40 by Leitz, Ernst