Question

what is refractive index?......

Answer 1

the ratio of the velocity of light in a vaccum to its velocity in as specified
medium
Hope u like this ans ..hit Thank u button

Answer 2

Refractive index, also called index of refraction, measure of the bending of a ray of lightwhen passing from one medium into another. If i is the angle of incidence of a ray in vacuum (angle between the incoming ray and the perpendicular to the surface of a medium, called the normal) and r is the angle of refraction(angle between the ray in the medium and the normal), the refractive index n is defined as the ratio of the sine of the angle of incidence to the sine of the angle of refraction; i.e., n = sin i / sin r. Refractive index is also equal to the velocity of light c of a given wavelength in empty space divided by its velocity v in a substance, or n = c/v.