What is called the absolute refractive index of a medium? Obtain the general from of Snell’s law in terms of refractive indices of two media?

The refractive index of medium with respect to the vacuum is called absolute refractive index.

Snell’s law in terms of refractive indices of two media: Let,

N₁ = absolute refractive index of medium 1.

N₂ = absolute refractive index of medium 2.

V₁ = velocity of light in medium 1.

V₂ = velocity of light in medium 2.

C = velocity of light in vacuum.

Then

N₁ = and N₂ =

∴

⇒ N₂₁ = ………….. (1)

Now According to Snell’s law

N₂₁ = …………….. (2)

From (1) and (2)

This is the general form of Snell’s Law.