Spectrometer (MCAT)

[BackToTheWall]

When using a spectrometer, to maximize absorbance, you use a light with a wavelength of maximum absorbance.

Question:
Why is the observed color complementary of the color absorbed?

I.e. if you absorb at a maximum wavelength of 400 (violet), the complementary color you see is yellow.

(trying to understand the mechanism behind it) thanks!

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[Like]

Photons of certain wavelength are absorbed = the material eats them up
Those that aren't absorbed, are reflected = the color you see because these photons flying into your retina

I pulled off a random image off of Google:

You see there's high absorbance in the red region and some slight absorbance in the blue.
Everything in between is not absorbed and will be reflected aka the color you see.

Edit: the above is all you need for the mcat. If you're interested in complementary colors from an artistic point of view here is a color wheel for you.

 

[dsoz]

Complimentary colors are the colors opposite each other on the color wheel.

yellow is opposite of violet. red is opposite of green. If you take the info from Like, the wavelengths that are opposite of those that are absorbed are those that you see. Since RED is absorbed in his/her image, you would see green.

dsoz