Physics - Geometrical Optics Question with Solution | TestHub

The relative refractive index of denser medium with respect to the rarer medium is

${\mathrm{\mu }}_{\mathrm{dr}}=\frac{{\mathrm{\mu }}_{\mathrm{d}}}{{\mathrm{\mu }}_{\mathrm{r}}}$

$\sin {\mathrm{i}}_{\mathrm{c}}=\frac{1}{{\mathrm{\mu }}_{\mathrm{dr}}}=\frac{{\mathrm{\mu }}_{\mathrm{r}}}{{\mathrm{\mu }}_{\mathrm{d}}}=\frac{{\mathrm{v}}_{\mathrm{d}}}{{\mathrm{v}}_{\mathrm{r}}}$

$\sin {30}^{\mathrm{o}}=\frac{{\mathrm{V}}_{\mathrm{d}}}{3\times 10^8}$

$\Rightarrow \mathrm{ }\mathrm{ }{\mathrm{v}}_{\mathrm{d}}=1.5\times 10^8 \mathrm{m} {\mathrm{s}}^{-1}$