Physics - Geometrical Optics Question with Solution | TestHub

Velocity of light waves in material is $v=\mathrm{v}\lambda \dots (i)$ Refractive index of material is $\mu =\frac{c}{v}\dots (ii)$ where $c$ is speed of light in vacuum or air. or $\mu =\frac{c}{v\lambda }\dots (iii)$ Given, $v=2\times 10^{14}\mathrm{Hz}$, $\begin{array}{rl}\lambda & =5000\mathring{A}=5000\times 10^{-10}\mathrm{m},\\ c& =3\times 10^8\mathrm{m}/\mathrm{s}\end{array}$ Hence, from Eq. (iii), we get $\mu =\frac{3\times 10^8}{2\times 10^{14}\times 5000\times 10^{-10}}=3.00$