GEOLOGY

Detailed explanation-1: -Refractive index of a medium is always greater than 1 (it cannot be less than 1) because the speed of light in any medium is always less than that in a vacuum.

Detailed explanation-2: -The absolute refractive index (n=c/v) of any medium is always greater than 1, because speed of light in any medium is always less than that in vacuum (i.e v<c).

Detailed explanation-3: -Most plastics have refractive indices in the range from 1.3 to 1.7, but some high-refractive-index polymers can have values as high as 1.76. For infrared light refractive indices can be considerably higher. Germanium is transparent in the wavelength region from 2 to 14 µm and has a refractive index of about 4.

Detailed explanation-4: -A refractive index of zero implies that light enters a state of quasi-infinite phase velocity and infinite wavelength. It also means that every point within the metamaterial experiences a quasi-uniform phase of the light wave present, as though all the dipoles inside the metamaterial are oscillating in unison.

Detailed explanation-5: -The vacuum has a refractive index of 1. The refractive index of other materials can be calculated from the above equation. Higher the refractive index, the higher the optical density and slower is the speed of light.