^{dear sir/madam no link please ,please explain the relation between the refractive index and the speed of light properly​}

Dear Student.

Refractive index of the medium is the ratio of the speed of light in vaccume to the speed of light in medium.$$\begin{gathered} Refrective index of medium =\frac{Speed of light in vaccume}{Speed of light in medium.} \\ This means if the refrective index of medium is more the speed of the light will be less. \\ lets say if the the refrective index of glass is 1.5 then the speed of light in glass will be 1.5 times less then the vaccume. \end{gathered}$$

regards.