If a diamond has a refractive index of 2.42, what is the speed of light in the diamond? - Leaving Cert Physics - Question (e) - 2013

Given the refractive index $n = 2.42$, we can rearrange the formula to find $c_2$:

$c_2 = \frac{c_1}{n}$

Substituting the known values:

$c_2 = \frac{3 \times 10^8 \text{ m/s}}{2.42}$

Performing the division gives:

$c_2 \approx 1.24 \times 10^8 \text{ m/s}$

Thus, the speed of light in the diamond is approximately $1.24 \times 10^8$ m/s.