Question
Find out from Table 2, the medium having highest optical density. Also, find the medium with lowest optical density.
| Material medium | Refractive index |
| Canada balsam | $1.53$ |
| Rock salt | $1.54$ |
| Carbon disulphide | $1.63$ |
| Dense flint glass | $1.65$ |
| Ruby | $1.71$ |
| Sapphire | $1.77$ |
| Diamond | $2.42$ |