Question

A ray of light of frequency of $5\times {10}^{14}Hz$ is passed through a liquid. The wavelength of light measured inside the liquid is found to be $450\times {10}^{-9}m$. Calculate refractive index of the liquid.

Answer 1

$velocity=wavelength\times frequency$

$v=450\times {10}^{-9}\times 5\times {10}^{14}$

$v=2.25\times {10}^{8}m/s$

Speed of light in vacuum is $c=3\times {10}^{8}m/s$

$\eta =\frac{3\times {10}^8}{2.25\times {10}^8}=1.33$