Im trying to find the indexes of refraction for my Dispersion of a Glass Prism lab.
Specifically I need to use Cauchy's equation to find the index of refraction for different wavelengths.
$$
n=a+\dfrac{b}{\lambda^2}
$$
This is what the step says: Convert the wavelengths to μm. Make a table containing the quantities wavelength,
wavelength-2, and index of refraction.
I made a graph but Im still not clear on what values a and b would be
This is my data so far
Best Answer
Some minor points: First, the units of $\lambda^2$ will be $(\mu m)^2$. Second it seems you are asking for $a, b$ so that you can determine $n$?
In fact, what is more often done is to plot $n$ versus $1/\lambda^2$ to determine $a, b$. At the moment you can't do anything (unless you follow Frobenius and look up $a, b$, however this means you know the material, but it may be a composite material or not listed or depend on a host of other issues), the suggestion is "Make a table containing the quantities wavelength, 1/(wavelength)$^2$, and index of refraction."
So, you need to construct a table with two columns: In the first column you have your measured values of refractive index and in the second column you have the corresponding values of $1/\lambda^2$.