Question

The speed of light in air is 3*10raised to 3 m/s. If the refractive index of diamond is 2.42, find the speed of light in diamond.

Answer 1

RI (r)= speed of light in air(c)/speed of light in medium(a)
r= c/a
a = c/r
a = 3 x 10⁸/2.42
a = 1.24 x 10⁸ m/s is the answer

Answer 2

μ of diamond = 2.42 = $\frac{speed\ of\ light\ in\ vacuum }{ speed\ of\ light\ in\ diamond}$

Speed of light in diamond = speed of light in vacuum / μ
$= \frac{3 * 10^8 m/sec}{2.42} \\ \\ = 1.239 * 10^8 m /sec$