Question

the reflective index of carbon di sulfide is 1.63 what is meaning of this statement in relation to speed of light

Answer 1

Refractive index of a medium is the ratio of speed of light in vacuum to the speed of light in the medium. So, higher the refractive index, lesser is the speed of light. Hence, as the index is 1.63, it is greater than 1,i.e, speed of light in carbon disulphide is lesser than speed of light in vacuum by a factor of 1.63.

Answer 2

The refractive index of carbon di sulphide is 1.63 means that ratio of speed of light in air or vacuum to speed of light in carbon di sulphide is 1.63
refractive index will always be either equal to or greater than 1 bcoz speed of light is maximum in air or vacuum