extinction coefficient?

Question

okay im asked to arrange compounds that were tested in order by increasing extinction coefficients. There is only 2, 2.263 for CuSO4 and 3.326 for CoCl2.

Now it says to discuss what this order means in terms of ability of these substances to absorb light. Here is what I got from wiki:

The extinction coefficient for a particular substance is a measure of how well it absorbs electromagnetic radiation (EM waves). If the EM wave can pass through very easily, the material has a low extinction coefficient. Conversely, if the radiation hardly penetrates the material, but rather quickly becomes "extinct" within it, the extinction coefficient is high.

So I guess that would mean that the higher the extiction coeffcient the better the ability to absorb light?

It also asks to provide a scenario where the above order might change.) In other words conditions the substance with the highest extinction coefficient above may no longer be the highest)

I guess this would be under a different wavelength of light?

Answer 1

Yes, to both your questions. The higher the extinction coefficient, the better the ability of that substance to absorb EM at that frequency. And yes, changing the frequency that's used in the absorption experiment will affect the value of the extinction coefficient. Chemical species will absorb radiation well at some frequencies and not so well at other frequencies.

Answer 2

Extinction Coefficient