The speed of light in a certain transparent material is $2.25\times 10^8{\text{m s}}^{-1}$. Calculate the refractive index of the material.

Step-by-step solution

1. Refractive index $n$ is defined as $n=\frac{c}{v}$, where $c=3.0\times 10^8{\text{m s}}^{-1}$ is the speed of light in vacuum and $v$ is the speed in the material.
2. Substituting the given values, $n=\frac{3.0\times 10^8}{2.25\times 10^8}$.
3. Perform the division: $\frac{3.0}{2.25}=1.33$.
4. Hence, the refractive index of the material is $1.33$.

Concept tested: Refractive index definition

Published 23 August 2026 · How this solution was prepared and checked

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