Question
If $\varepsilon_0$ and $\mu_0$ are the permittivity and permeability of free space, and $\varepsilon$ and $\mu$ are the corresponding quantities for a medium, then the refractive index of the medium is
If $\varepsilon_0$ and $\mu_0$ are the permittivity and permeability of free space, and $\varepsilon$ and $\mu$ are the corresponding quantities for a medium, then the refractive index of the medium is