Refractive Index for some common Liquids, Solids and Gases
Some common fluids and their refractive index
Refraction is an effect that occurs between transparent materials of different densities.
The Refractive Index - n - of a medium is a measure for how much the velocity of light is reduced inside the medium. The velocity of light in a medium can be expressed as
v = c / n (1)
where
v = velocity of light in the medium (m/s, ft/s)
c = speed of light in air or vacuum - approximately 3 108 m/s (or 299792458 m/s)
n = refractive index
The index of refraction is defined as
- "the speed of light in vacuum divided by the speed of light in the medium".
Index of Refraction for Vacuum
- n = 1.00
Refractive Indices for some common Gases
| Gas | Refractive Index - n - |
|---|---|
| Acetone | 1.001090 |
| Air (-15oC) | 1.00030942 |
| Air (0oC) | 1.00029238 |
| Air (15oC) | 1.00027712 |
| Air (30oC) | 1.00026337 |
| Air (60oC) | 1.00023958 |
| Alcohol, ethyl | 1.000878 |
| Alcohol, methyl | 1.000586 |
| Ammonia | 1.000376 |
| Argon | 1.000281 |
| Benzene | 1.001762 |
| Bromine | 1.001132 |
| Carbon dioxide | 1.000449 |
| Carbon disulphide | 1.001481 |
| Carbon monoxide | 1.000338 |
| Chlorine | 1.000773 |
| Chloroform | 1.001450 |
| Ether, ethyl | 1.001533 |
| Ether, methyl | 1.000891 |
| Helium | 1.000035 |
| Hydrochloric acid | 1.000447 |
| Hydrogen | 1.000132 |
| Methane | 1.000444 |
| Nitric oxide | 1.000297 |
| Nitrogen | 1.000298 |
| Nitrous oxide | 1.000516 |
| Oxygen | 1.000271 |
| Pentane | 1.000686 |
| Sulphur dioxide | 1.000686 |
| Water vapor | 1.000261 |
Index of Refraction for common Liquids
| Fluid | Refractive Index - n - |
|---|---|
| Acetic Acid | 1.37 |
| Acetone | 1.36 |
| Alcohol, ethyl (ethanol) | 1.36 |
| Alcohol, methyl (methanol) | 1.33 |
| Alcohol, propyl | 1.38 |
| Aniline | 1.586 |
| Benzene | 1.501 |
| Benzyl benzoate | 1.568 |
| Carbon disulfide | 1.63 |
| Carbon tetrachloride | 1.46 |
| Chlorobenzene | 1.525 |
| Chloroform | 1.44 |
| Decane | 1.41 |
| Dodecane | 1.41 |
| Ether | 1.35 |
| Ethylene glycol | 1.43 |
| Ethyl salicylate | 1.523 |
| Ethyl cinnamate | 1.559 |
| Trichlorofluoromethane refrigerant R-11 | 1.37 |
| Dichlorodifluoromethanerefrigerant R-12 | 1.29 |
| Chlorodifluoromethane refrigerant R-22 | 1.26 |
| Furan | 1.47 |
| Glyserine (Glycerol) | 1.47 |
| Heptane | 1.38 |
| Hexane | 1.37 |
| Hydrogen liquid | 1.0974 |
| Methyl salicylate | 1.538 |
| Methylene iodine | 1.737 |
| Milk | 1.35 |
| Octane | 1.40 |
| Oil, cedar | 1.516 |
| Oil, vegetable 50oC | 1.47 |
| Oil, oiive | 1.46 |
| Oil, turpentine | 1.47 |
| Paraldehyde | 1.405 |
| Parafin, liquid | 1.48 |
| Propane | 1.34 |
| Propylene | 1.36 |
| Propylene glycol | 1.43 |
| Quinoline | 1.627 |
| Toluene | 1.497 |
| Turpentine (wood) | 1.47 |
| Water 0oC | 1.33346 |
| Water 20oC | 1.33283 |
| Water 100oC | 1.31766 |
Example - Speed of Light in Air
The speed of light in air can be calculated as
v = (299792458 m/s) / 1.000293
= 299704645 m/s
Example - Speed of Light in Water
The approximate speed of light in water can be calculated as
v = (3 108 m/s) / 1.33
= 2.26 108 m/s
Index of Refraction for some common Solids
| Solid | Refractive Index - n - |
|---|---|
| Crown glass | 1.5 - 1.62 |
| Diamond | 2.417 |
| Flint glass | 1.57 - 1.75 |
| Ice | 1.31 |
| Plexiglas | 1.49 |
| Salt | 1.52 |
Example - Speed of Light in Glass
The approximate speed of light in glass can be calculated as
v = (3 108 m/s) / 1.6
= 1.88 108 m/s
Index of Refraction for some selected Polymers
| Polymer | Refractive Index - n - |
|---|---|
| Acrylic | 1.48 - 1.50 |
| Celulose Acetat | 1.46 - 1.50 |
| Epoxy | 1.6 |
| HDPE | 1.5 |
| Polycarbonate | 1.59 |
| PTFE | 1.35 |
| Polyester | 1.50 - 1.58 |
| Polystyrene | 1.6 |
| Vinylidene chloride | 1.6 - 1.63 |
