# Light is travelling in quartz, which has an index of refraction of 1.458. How fast does light travel in quartz?

Apr 1, 2018

Approximately $2.06 \cdot {10}^{8}$ meters per second.

#### Explanation:

Well, the equation for the refractive index is:

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

• $c$ is the speed of light in a vacuum

• $v$ is the speed of light through the medium

And so, we get,

$1.458 = \frac{3 \cdot {10}^{8} \setminus \text{m/s}}{v}$

$v = \frac{3 \cdot {10}^{8} \setminus \text{m/s}}{1.458}$

$\approx 2.06 \cdot {10}^{8} \setminus \text{m/s}$