Question

The refractive indices of water and diamond are $\frac{4}{3}$ and $2.42$ respectively. Find the speed of light in water and diamond.
($c=3\times {10}^{8}m/s$)

Answer 1

Given,

Refractive index of water, ${\mu }_{{}_W}=\frac{4}{3}$

Refractive index of diamond, ${\mu }_{{}_D}=2.42$

Refractive index of any medium=$\mu$ = speed of light in air / speed in the medium

${\mu }_{{}_W}=\frac{4}{3}=\frac{c}{{}_{V_W}}$

$\therefore$ ${}_{V_W}=\frac{c\times 3}{4}=2.25\times {10}^{8}m/s$

${\mu }_{{}_D}=2.42=\frac{c}{{}_{V_D}}$

$\therefore$ ${}_{V_D}=\frac{c}{2.42}=1.24\times {10}^{8}m/s$