# What does A485 mean? And what does the values on the y-axis expresses?

This question is from past exam paper. I don't want an answer to the multiple choice question below, I just want to understand what A485 means in the context of the question.

• This is a homework question. We ‎have a policy which states that you should show your thoughts and/or efforts into solving the ‎problem. It'll make us certain that we aren't doing your homework for you. Otherwise, this ‎question may get closed.‎ – M.A.R. Dec 8 '15 at 18:40
• Then do as instructed; put in precise details of everything you did. Then I'll vote to reopen your question so it'd get answered. – M.A.R. Dec 8 '15 at 19:27
• What did you do that didn't get answers? Enlighten us by editing your question. – M.A.R. Dec 8 '15 at 19:43
• I got it. I think, I don't need to edit the question. May be, if I ask next time any question I will try to ask according to the instruction. – Ahmad Dec 8 '15 at 20:01
• @Ahmad For further reference, please also keep the following in mind: A screenshot or picture of an exercise is not searchable. Please consider rewriting it, so that it can be of help for future visitors. Further I invite you to take the tour to learn about the site and review the homework policy. – Martin - マーチン Dec 9 '15 at 4:37

$A_{485}$ means the same thing as the text of the multiple choice question "absorbance of the solution at 485 nm".