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## Absorption vs. Transmission

I'm a little confused, we have tested chemical concentrations based on how much light it can absorb. What i don't understand is why something can have a reading of 60% transmission yet also have an absorption of 22.2% via the equation A = LOG(1/T), T being tranmission, A being absorption. Seems like it should be a 40% absorption. Then i realized i might not quite understand what it means when a spectrometer is reading "Absorption and Transmission". Can someone explain?
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 The rest goes to scattering processes I guess. One can split the mass-energy absorption factor to elastic and inelastic scattering and photoabsorption.
 Recognitions: Science Advisor You may have got something wrong with your equation. Maybe you should consult the manual again.

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## Absorption vs. Transmission

 Quote by Ich You may have got something wrong with your equation. Maybe you should consult the manual again.
No that's how the math works. The meter has a transmission and an absorption scale on the same dial going opposite ways but the Absorption is logarithmic.
 Recognitions: Gold Member Science Advisor Reflection accounts for some of the difference.... $$R + T + A = 1$$ for all processes.
 Recognitions: Science Advisor Hey, when T<0.1 -> A>1. That surely does NOT work. You must have forgot something crucial.
 Ich is right, not only does that allow for absorption to be more than 100%, but A+T > 100% whenever the transmission is less than 13.7%.

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