Figure (a) below shows the basic structure of a 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, by the distance i among the lens and the film set at f = 6.0 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 = 143 cm, and the lens–film distance is adjusted thus that an inverted real image forms on the film (figure (b) below). (a) What is the lens–film distance i now? (b) By how much was distance i changed?