Question

What is the physical significance of refractive index?

• A. It tells how faster the light is moving in that medium
• B. It tells the density of the medium
• C. It says how much air resistance the medium has
• D. It doesn't have any significance

Answer 1

The correct option is A

It tells how faster the light is moving in that medium

The factor by which the speed of light gets decreased is governed by one of the optical property of the medium called refractive index.
It is defined as, n = $\frac{\text{Speed of light in vacuum}}{\text{Speed of light in medium}}$
where, n is the refractive index of the medium.