The refractive index, also called the index of refraction, is defined as the quotient of the speed of light as it passes through two media. It is a dimensionless number that depends on temperature and on the wavelength of the light beam. In simple words, the refractive index describes how fast a light beam travels through media, and this relationship is described by the formula:

*n* = *c* / *v*

Where:

*n* is the index of refraction*c* is the speed of light in a vacuum (or air)*v* is the speed of light in the media (e.g. water, olive oil, etc.)

On this page you will gain essential knowledge about refractive index and refractive index measurements.

**Learn more about the definition of refractive index, applications, how to measure it, Snell's Law and much more.**