Question

The refractive index of glass is 1.5. What is the speed of light in glass? (Speed of light in vacuum is $3.0\times {10}^{8}m{s}^{-1})$

Answer 1

We know that refractive index of light is defined by $\eta =\frac{speedoflightinvaccum}{speedoflightthatmedium}$

$\eta =\frac{3\times {10}^8}{v}=1.5$

$v=2\times {10}^{8}m/s$