This is a home work question. Please show some work. HINT - Use Beer–Lambert law.

okay so this is an equation used: Abs=ecx and i believe i have all the numbers i needed to plug it in so i did Abs=(6220L/mole.cm)(1.5cm)(0.8mM) and then find abs right? is this all i need? because "e" is suppose to be molar extinction coefficient in (L/moles.cm) "x" is 1.6cm and "c" is suppose to be the concentration of macromolecule in m/L. but i am not sure what to do with 11 ml, or do i even bother with it? any help would be much appreciated

You have to assume that 11 ml would be enough to fill the cuvette. Seems like more than enough. 1.6x1.6 cm cross section and 4 cm tall . // LOL - Spell check wants to use its magic to change cuvette to corvette. Gosh it should be that easy...

Not quite. What are you supposed to be calculating?

Calculate the percentage light transmission of this sample at 340nm

And what does you equation calculate?

well yes because i need to find Abs which is the light transmission

or is that the absorbance? but either way if it is the absorbance couldn't i subtract whatever i get from abs to get the transmission using log(1/abs)

The point is that you calculate the %T from the Abs. The two things are not one and the same.

i could really use some help, i did like millions of beers law practice and i am stuck on two questions and this is one of them

$T = 10^{-A}$ is equation to convert, 100T = %T

yes but is to get Abs right? like on my set up on my first comment based on the question?

EDit equion by adding a section "WORK" show your calculations...// Or add anaswer showing work...

Abs=(6220L/mole.cm)(1.5cm)(0.8mM)=7464?

then when used T=10^-A that gave me a huge number

What is a mM? ........

it is in millimeter

Welcome chem.SE. Please note that it's not any homework helping site. And questions like this one will surely attract any attention because it's an conceptual misunderstanding of yours. Please, be careful.

In your equation 'Abs' is usually called optical density and is what a spectrophotometer conventionally plots vs wavelength in an absorption spectrum. You need to convert the amount of NADH into concentration; I'm not sure if by $0.8$ micromoles you mean a concentration or just this amount in $11$ ml.

Well it should be $\mu\text{M}$ or micromoles

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