Refractive Index/ Absolute refractive Index

 It is defined as the ratio of speed of light in vacuum to the speed of light in a certain medium. It is denoted with “n”.

* The speed of light in vacuum is denoted with “c” and its value is equal to 3x 10⁸ m/sec..

* Let the speed of light in certain medium be “v”, then

* Absolute refractive Index= Speed of light in vacuum/Speed of light in certain medium

                                   n= c/v

* Since it is a ratio, it will not have any units. So we can say it is a dimensionless quantity.

* The speed of light in any transparent or certain medium will be always less than or smaller than “c”.

*  Refractive Index will give you an index of how fast the light wills travel in a medium.

* Refractive index of the medium     α    1/ speed of light in the medium.

     i.e. the speed of light in the medium is low when the refractive index of the medium is high and vice versa.

* The refractive index “n” means that the speed of light in that medium is nth part of speed of light in vacuum.

      Refractive Index depending factors:

1. Wavelength of light.

2.  Nature of material.

                                                  Refractive Indices of some material