# The refractive index of diamond is 2.42. What is the meaning of this statement?

A Refractive index is defined as the ratio of the speed of light in a vacuum to its speed in a specific medium.

## Refractive index formula

The refractive index is a dimensionless quantity. It’s a number that shows how much slower a light wave will pass through material than it would in a vacuum. The refractive index (n) is the velocity of light in a vacuum divided by light in a medium. The refractive index formula is expressed as,

$$n = \frac{c}{\nu }$$

Where,

• n is the refractive index
• c is the velocity of light in a vacuum (3 × 108 m/s)
• v is the velocity of light in a substance

### What is the meaning of the refractive index of diamond is 2.42?

The refractive index of diamond is 2.42. This means that the speed of light in a diamond will reduce by a factor of 2.42 compared to its speed in air.
In other words, the speed of light in a diamond is 1/2.42 times the speed of light in a vacuum. Since the refractive index of diamond is quite high, it means that the diamond’s speed in diamond is deficient.