Question

what is refractive index​

Answer 1

Answer:

the ratio of the velocity of light in a vacuum to its velocity in a specified medium is called refractive index.

Answer 2

Refractive index of second medium with respect to first medium is defined as the ratio of sine of angle of incidence to ratio of sine of angle of refraction is constant for a given pair of media.

$ref \: index = \frac{ \sin \: i }{ \sin \: r }$