Question

What is the speed of light in a glass if you know that the speed of light in a vacuum is c=3.0x108 m/s and the refractive index of the glass is 1.52?

Answer 1

In order to calculate the speed of light in the glass, we can use the formula below:

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

Where n is the index of refraction, c is the speed of light in a vacuum and v is the speed of light in the corresponding index of refraction.

So we have:

$\begin{gathered} 1.52=\frac{3\cdot10^8}{v}\\ \\ v=\frac{3.10^8}{1.52}\\ \\ v=1.97\cdot10^8\text{ m/s} \end{gathered}$

Therefore the speed of light in this glass is 1.97 * 10^8 m/s.