Question

what is the difference between absolute refractive index and refractive index​

Answer 1

Answer:

Relative refractive index:

Light travels fastest in vacuum and with almost the same speed in air, i.e. c = 3 × 108 m s−1. In other media, its speed is relatively less. The value of refractive index for a given pair of media depends on the speed of light in the two media.

The refractive index of medium 2 with respect to medium 1 is given as,

begin mathsize 12px style straight n subscript 21 equals fraction numerator Speed space of space light space in space medium space 1 over denominator Speed space of space light space in space medium space 2 end fraction end style

Absolute refractive index:

If medium 1 is vacuum or air, then the refractive index of medium 2 is considered with respect to vacuum. This is known as the absolute refractive index of the medium.

The absolute refractive index is given as,

begin mathsize 14px style straight n subscript straight m equals fraction numerator Speed space of space light space in space vacuum over denominator Speed space of space light space in space medium end fraction end style

The absolute refractive index of a transparent medium is always greater than 1.