Figure a, 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, with the distance i between the lens and the film set at f = 5.0cm, 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 = 100cm, and the lens-film distance is adjusted so that an inverted real image forms film (Figure b).

(a) What is the lens-film distance i now?

(b) BV how much was distance i changed?