Refraction is the bending of a wave when it enters a medium where it's speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media. The amount of bending depends on the indices of refraction of the two media and is described quantitatively by Snell's Law.
Following table shows refraction index for different mediums.
Index of Refraction
| Material | Index |
|---|---|
| Vacuum | 1.00000 |
| Air at STP | 1.00029 |
| Ice | 1.31 |
| Water at 20 C | 1.33 |
| Acetone | 1.36 |
| Ethyl alcohol | 1.36 |
| Sugar solution(30%) | 1.38 |
| Fluorite | 1.433 |
| Fused quartz | 1.46 |
| Glycerine | 1.473 |
| Sugar solution (80%) | 1.49 |
| Typical crown glass | 1.52 |
| Crown glasses | 1.52-1.62 |
| Spectacle crown, C-1 | 1.523 |
| Sodium chloride | 1.54 |
| Polystyrene | 1.55-1.59 |
| Carbon disulfide | 1.63 |
| Flint glasses | 1.57-1.75 |
| Heavy flint glass | 1.65 |
| Extra dense flint, EDF-3 | 1.7200 |
| Methylene iodide | 1.74 |
| Sapphire | 1.77 |
| Rare earth flint | 1.7-1.84 |
| Lanthanum flint | 1.82-1.98 |
| Arsenic trisulfide glass | 2.04 |
| Diamond | 2.417 |