## Light absorption through water

1. The problem statement, all variables and given/known data
I am currently doing a biology honours project at university and have been stumped by a fairly basic physics hurdle. I need to know the equation to calculate the amount of light absorbed by water/unit depth. I have tried to find the equation all over but cannot find anything. Im sure i did this in A-Level physics but i really cant remember -_-

Any help would be greatly appreciated
Thanks

2. Relevant equations

3. The attempt at a solution
 PhysOrg.com science news on PhysOrg.com >> King Richard III found in 'untidy lozenge-shaped grave'>> Google Drive sports new view and scan enhancements>> Researcher admits mistakes in stem cell study
 Recognitions: Homework Help The light absorption in water depends on the wavelenght of the light. It is fairly law for the visible light but strong for UV and infrared. See at http://upload.wikimedia.org/wikipedi...n_spectrum.png. If you have the absorption coefficient alpha in reciprocal centimeters, multiply it by the thickness (in cm units) and you get the "absorbance" (A) of the water layer of the given thickness. The intensity of the light decreases with the ratio exp(-A) or 10-A, depending on the way alpha was given. If the intensity of the incident light is I0, it decreases to I0*10-A after travelling through a distance d in water. ehild