When you use a spectrophotometer, should you set the wavelength of light to be the same color as that of the solution, or would a different color be more appropriate? Explain.

Answer 1

I suppose it depends upon what you are trying to do with the spectrophotometer and the sample. From the tenor of your question, I guess you are talking about quantitative analysis. For that you set the instrument to absorb the most light passing through the sample. That will be the complementary color of the sample. If you set the instrument to be the same color as the sample then the sample absorbs less radiation than it will at the complementary color and that procedure will have the least sensitivity.