# Color transition [closed]

We have to determine which method is true in order to find which color is absorbed and which one is transmitted?

I have read in an example that $\ce{Cu^{2+}}$ absorbs red light but transmits blue.This is true if we see pyramid but not with respect to circle....How could we make jugdement in exams while solving mcq related to it?

The problem with your color wheel is that it presents each color as an equal wedge. They are not. Note that red is 180 nm in width and orange is 40 nm in width. Here is a better one that I made:

As you can see, there is a range of red wavelengths that can be absorbed to get transmittance in blue.

• ...then what do you think about pyramidal cycle....is it correct? – M.Naeem Ahmad Apr 26 '17 at 9:44
• It is better than the circle, but it is still flawed in that it represents each color as equal width. – Ben Norris Apr 26 '17 at 10:36