Physics - Current Electricity Question with Solution | TestHub

We know that the refractive index of a medium is given by $\mu =\frac{{\mathrm{c}}_0}{\mathrm{c}}$ Where $\mathrm{c}=$ velocity of light in the medium ${\mathrm{c}}_{\mathrm{o}}=$ velocity of light in vacuum For crown glass, $1.5=\frac{{\mathrm{c}}_{\mathrm{o}}}{2\times 10^8}$ ...(1) For flint glass, $1.8=\frac{{\mathrm{c}}_{\mathrm{o}}}{\mathrm{c}}$ ...(2) Dividing (2) by (1), we get $\frac{2\times 10^8}{\mathrm{c}}=\frac{1.8}{1.5}$ or $\mathrm{c}=\frac{1.5\times 2\times 10^8}{1.8}\mathrm{m}/\mathrm{s}=1.67\times 10^8\mathrm{m}/\mathrm{s}$