Halliday, Resnick & Walker — Images: Problem 46

46 Figure 34-32a shows the basic structure of an old film camera. A lens can be moved forward or back to produce an image on film at the back of the camera. For a certain camera, with the distance \( i \) between the lens and the film set at \( f = 5.0 \text{ cm} \), parallel light rays from a very distant object \( O \) converge to a point image on the film, as shown. The object is now brought closer, to a distance of \( p = 120 \text{ cm} \), and the lens–film distance is adjusted so that an inverted real image forms on the film (Fig. 34-32b). (a) What is the lens–film distance \( i \) now? (b) By how much was distance \( i \) changed?