Question

The speed of light in diamond is 125,000 km $m{s}^{-1}$. What is its refractive index? (Speed of light in air = 3 $\times {10}^{8}m{s}^{-1}$ )

Answer 1

Speed of light in vacuum = 3 $\times$ ${10}^8$ m/s
Speed of light in Dimond = 125000 $\times$ 1000 m/s or 1.25 $\times$ ${10}^8$ m/s
We know, refractive index = $\frac{Speedoflightinvacuum}{Speedoflightinamedium}$
Refractive index = $\frac{3\times {10}^8}{1.25\times {10}^8}$ = 2.4