15) Which of the following(s) may cause an instrumental deviations in Beer's law? I- Polychromatic light source II- Stray light III - Cell/Cuvette variability A) Only II B) Only III C I and II D) II and III E) I, II and III

E) I, II and III<br /><br />All three factors mentioned can cause instrumental deviations in Beer's law:<br /><br />I - Polychromatic light source: If the light source used is polychromatic, different wavelengths may interact differently with the solution, leading to inaccurate measurements of absorbance.<br /><br />II - Stray light: Stray light refers to light that is not directed through the sample and can interfere with the measurement of absorbance. It can cause inaccuracies in the determination of the concentration of a substance.<br /><br />III - Cell/Cuvette variability: Variability in the cell or cuvette used for the measurement can also cause deviations in Beer's law. Factors such as the quality of the cuvette, its cleanliness, and the alignment of the light path can all affect the measurement.<br /><br />Therefore, all three factors (I, II, and III) can cause instrumental deviations in Beer's law.