What will be the Refractive index of a medium in which light travels with the speed of$1.4 \times {10}^8\frac{m}{s}$? Given that speed of light in vacuum is$3 \times {10}^8\mathit{ m}/s$.

The Refractive index of a medium in which light travels with the speed of$1.4 \times {10}^8\mathit{ m}/s$ will be$2.14$.
Law of Refraction States that the incident ray refracted ray and the normal to the interface of two media at the point of an incident all lay on the same plane. 
Given, 
Speed of light in vacuum $= 3 \times {10}^8\mathit{ m}/s$
Speed of light in the medium $= 1.4 \times {10}^8\mathit{ m}/s$
Refractive Index of the medium, ${\mu }_m =$ $\frac{\mathrm{Speed} \mathrm{of} lig\mathrm{ht} \mathrm{in} vacuum}{\mathrm{Speed} \mathrm{of} lig\mathrm{ht} \mathrm{in} medium}$
                                                            $=\frac{3 \times {10}^8}{1.4\times {10}^8}$
                                                                    $=2.14$