Playing around with achromatic pairs

While trying to come up with some “different” questions about lenses that have some connection with students’ everyday experiences, I started thinking about chromatic aberration and the method of correction using achromatic pairs of lenses. Although most current introductory physics textbooks provide few (if any) quantitative details on achromatic lenses, I show that the analysis is not only very straightforward, but it can help reinforce understanding of some of the essential concepts appropriate to lenses and can offer plenty of opportunity for variety. Consequently, instructors searching for alternative areas to explore and challenge their students may wish to pose questions, set as! ! signments or research papers, etc., in this general area and feel confident that they fall well within the capabilities of most students.