The refractive index of a medium is the amount by which the speed (and wavelength) of electromagnetic radiation (light) is reduced compared with the speed of light in a vacuum.
- Refractive index (or, index of refraction) is a measurement of how much slower light travels through any given medium than through a vacuum.
- The concept of refractive index applies to the full electromagnetic spectrum, from gamma-rays to radio waves.
- The refractive index of a medium is a numerical value and is represented by the symbol n.
- Because it is a ratio of the speed of light in a vacuum to the speed of light in a medium there is no unit for refractive index.
- The refractive index of water is 1.333. The ratio is therefore 1:1.333.
- If 1 is divided by 1.333 we find that light travels at 0.75 the speed through glass compared to a vacuum.
- As light undergoes refraction its wavelength changes as its speed changes.
- As light undergoes refraction its frequency remains the same.
- The energy transported by light is not affected by refraction or the refractive index of a medium.
- The colour of refracted light perceived by a human observer does not change during refraction because the frequency of light and the amount of energy transported remain the same.
https://en.wikipedia.org/wiki/Refractive_index
