Refractive index as a function of the concentration of a sugar solution

[RickRazor]

We recently performed an experiment with the idea to find refractive index of medium (water) as a function of wavelength of light. We then added some sugar to see how the refractive index changes with concentration of sugar solution. We got the following graphs.

Are the relationships actually linear? Or are these just limiting cases?

 

[mfb]

Nearly nothing is exactly linear, but for small changes most things are approximately linear.

With the wavelength it is easy to see that it cannot continue like that - you would get negative values for very long wavelengths.

 

[Andy Resnick]

We recently performed an experiment with the idea to find refractive index of medium (water) as a function of wavelength of light. We then added some sugar to see how the refractive index changes with concentration of sugar solution.

Are the relationships actually linear?

Why did you assume there is a linear relationship?