The refractive index is the relationship between the speed of light and the speed at which light travels. The refractive index of light in glass is about 1.5 which means that light is 1.5 slower in that medium. The light changes direction when is incident to another medium at an angle, otherwise, you will not notice.

Index of refraction n=cv n = c v , where v is the speed of light in the material, c is the speed of light in vacuum, and n is the index of refraction.

The refractive index is the measure of bending of a light ray when passing from one medium to another. It can also be defined as the ratio of the velocity of a light ray in an empty space to the velocity of light in a substance, n = c/v.

The following table organizes gemstones from highest to lowest refractive indices….Refractive Indices and Double Refraction Values.

Refractive index is a measure of how much speed of light changes when it enter the medium from air. Absolute refractive index is the ratio of speed of light in vacuum or air to speed of light in the medium.

1n2 means refractive index of the second medium with respct to the first medium.

1

This is because the light ray bends only when travelling from the rarer medium (medium 1) to the denser medium (medium 2). As a result of this the refractive index is measured as the index of refraction (or bending of the light ray) in medium 2 to with respect to medium 1. Hence it is written as n21.

aμr/wμr=aμw.

a If n21 is the refractive index of medium 2 with respect to medium 1 and n12 the refractive index of medium 1 with respect to medium 2 then it should be clear that n12=1/n21 It also follows that if n32 is the refractive index of medium 3 with respect to medium 2 then n32 = n31 × n12 where n31 is the refractive index …

The law stating that if the direction of a light beam is reversed, despite the number of times the beam is reflected or refracted, it will follow the same path.

(a) From v=cn,v=3×108m/s4/3=2.25×108m/s. , (b) From n=cv=3×108m/s2×108m/s=1.5.

The critical angle occurs when the angle of incidence where the angle of refraction is 90°. The light must travel from an optically more dense medium to an optically less dense medium.

Critical angle, in optics, the greatest angle at which a ray of light, travelling in one transparent medium, can strike the boundary between that medium and a second of lower refractive index without being totally reflected within the first medium.