Final answer:
In the Beer-Lambert Law, 'A' stands for a. Absorbance, which measures the light absorbed by a sample at a specific wavelength and is used to calculate the concentration of that substance in the sample.
Step-by-step explanation:
In the context of the Beer-Lambert Law, the symbol 'A' represents a. Absorbance. Absorbance is a measure of the amount of light at a particular wavelength that is absorbed by a sample. Essentially, when light passes through a sample, some of it is absorbed by the molecules in the sample, and the remaining light exits on the other side.
The absorbance (A) is calculated by using the formula A = log(Io/I), where Io is the intensity of the incident light and I is the intensity of transmitted light. This value relates directly to the concentration of the absorbing substance in the sample, as determined by the equation Absorbance (at 260nm) = ε*c*l, where ε is the molar absorptivity or extinction coefficient, c is the concentration, and l is the path length through which the light travels.