# Light Speed in matter

Light Speed in matter from refractive index Calculator.

**Enter 'x' in the field to be calculated.**

This tool is a light speed in matter (air, glass, plexiglass,etc) calculator.

`v = c / n`

v : light speed in matter in meter per second (m/s)

c : light speed in vacuum in meter per second (m/s)

n : refractive index of medium

This tool let you also compute the refractive index of a medium given the light speed in this medium. To do so, simply input "x" in the field "refractive index (n)" and input the speed light value in the field "light speed (v)". The calculator applies then the following formula,

`n = c / v`

## Some examples

Refractive indexes and light speed in some mediums :

**Vacuum** : n = 1 , v = 299792458 m/s

**Water (T=20 degrees)** : n = 1.33 , v = 225407863 m/s

**Air** : n = 1 , v = 299792458 m/s

**Plexiglass** : n = 1.49 , v = 201202992 m/s

**Plastic** : n = 1.3 à 1.6 , v = 230609583 m/s (n = 1.3)

**Atmosphere** : n = 1 , v = 299792458 m/s

**Diamond** : n = 2.4175 , v = 124009290 m/s

**Ice** : n = 1.31 , v = 228849205 m/s

**Glycerine** : n = 1.47 , v = 203940448 m/s

**Huile** : n = 1.46 , v = 205337300 m/s

**Ethanol** : n = 1.3594 , v = 220532925 m/s

**Glass** : n = 1.5 , v = 199861639 m/s

**Polystyrene** : n = 1.2 , v = 249827048 m/s

## See also

Optics Calculators

Physics Calculators