Question

The refractive index of a certain substance is 1.5. Find the speed of light in this medium. Given that the speed of light in air is 3×10⁸ m/s

Answer 1

Step 1.

Given:

$\mu$$=1.5$

$c=3\times {10}^{8}m/s$

To find: $thespeedoflightinthismedium=v$

Step 2.

Calculation:

To find the speed of light in any medium we use the formula of $absoluterefractiveindex$ i.e.,

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

$1.5=\frac{3\times {10}^8}{v}$

$$\begin{gathered} Cross-multiplyingweget, \\ v=\frac{3\times {10}^8}{1.5} \\ v=2\times {10}^{8}m/s \end{gathered}$$

Hence, the speed of light in the given medium is $2\times {10}^{8}m/s$.