how do you calculate the refractive index?

Question

a_clan · Answer

n = sin i / sin r 
where i is angle of incidence and r is angle of refraction.
 Refractive index is also equal to the velocity c of light of a given wavelength in empty space divided by its velocity v in a substance, or 
n = c/v.

anonymous · Answer

how do i apply that to this question?

before entering the interior of the eye light has to travel through 2mm of cornea, which takes ca. 9.17ps (picoseconds). calc. the refractive index of the cornea.

anonymous · Answer

You know the speed of light in air.  You can calculate the speed of light in the eye, since you know the time it takes for the light to travel 2 mm.  Using the equation $$n=\frac{c}{v}$$ where v is the speed of light in a medium, and c is the speed of light in air, you can calculate the refractive index n.

anonymous · Answer

thank you

anonymous · Answer

what is the unit n?

anonymous · Answer

of n?

anonymous · Answer

since n is effectively a ratio between two speeds, or two wavelengths, it will not have any units, and is just a number.