xcX3v84RxoQ-4GxG32940ukFUIEgYdPy In case B, this would end up returning a bad extinction coefficient! You can experimentally determine this point either by testing the solution at different wavelengths or more accurately, running a program where the machine goes through it's entire wavelength range and measures absorption for you. You'll get a parabola where the maximum is your lambda max, so it's solvable by calculating the maxima if necessary (take the first derivative, set y'= 0, solve for y when x = (y'=0