Question

The refractive index of a material is 1.33. If the velocity of light in a vacuum is 3 x 10⁸ ms^-1, find the velocity of light in the material.

Answer 1

Step 1: Given data

The refractive index of a material ($\mathit{\mu }$) $=$1.33.

The velocity of light in a vacuum is 3 x 10⁸ ms^-1.

Step 2: Finding the velocity of light in the material

We know that,

$\text{The refractive index of a material (}\mu )=\frac{\text{Velocity of light in vacuum}}{\text{Velocity of light in the material}}$

Then,

$$\begin{gathered} 1.33=\frac{3\times {10}^8{\mathrm{ms}}^{-1}}{\text{Velocity of light in the material}} \\ \text{Velocity of light in the material}=\frac{3\times {10}^8}{1.33} \\ \text{Velocity of light in the material}=2.25\times {10}^8{\mathrm{ms}}^{-1}\text{.} \end{gathered}$$

Hence, the velocity of light in the material is $2.25\times {10}^8{\mathrm{ms}}^{-1}$.