Question

What is the absolute refractive index of air?

Answer 1

When the refractive index of a medium is considered with respect to the speed of light in vacuum, it is defined as the absolute refractive index of that particular medium.

Complete Step by Step Answer:
Refractive index of air $= \,\,1.0003$
Absolute refractive index of a medium is defined as the ratio of the velocity of light in the medium. If c is the velocity of light in vacuum and v in the medium then
$n\,\, = \,\,\dfrac{c}{v}$
Where $n\, = \,$ absolute refractive index
The value of the absolute refractive index can never be less than 1. This is so because light travels with the fastest speed in vacuum. The lower value of the absolute refractive index indicates a denser medium while a higher value indicates a rare medium.

Note: Significance of absolute refractive index is to explain the speed of light in medium. Speed of light is more if absolute refractive index is small and speed of light is less if absolute refractive index is high. Mainly used in refraction of light and light bends while change of medium is also due to difference in absolute refractive index of the medium.