# Blog

## How do you find the refractive index of a medium? The refractive index of a medium (n) is equal to the speed of light (c) divided by the velocity of light through the medium (v). Rearranging the equation allows us to see the relationship regarding v. The lower the refractive index, the faster the velocity of light. Medium A has the smaller refractive index.

## Why does the refractive index change?

• The refractive index is a common phenomenon, which is being observed almost daily. A light ray changes its direction when it travels from one medium to another medium. It happens due to the variation in the speed of light in each medium. The speed of light in a vacuum is 3x108 meters/second, and the speed of light in air is 2.98x108 meters/second.

## What is the refractive index and phase velocity?

• What is the refractive index of a medium ? What is the refractive index of a medium ? . The phase velocity is the speed at which the crests or the phase of the wave moves, which may be different from the group velocity, the speed at which the pulse of light or the envelope of the wave moves.

## How do you calculate the refractive index of a vacuum?

• The formula of refractive index is given as follows: n=c/v (1) where. n is the refractive index. c is the velocity of light in vacuum ( 3 × 108 m/s) v is the velocity of light in a substance. The vacuum has a refractive index of 1. The refractive index of other materials can be calculated using equation (1).  