Final answer:
The enlarging of an image on a film by a movie projector is an example of a dilation, a transformation that changes the size of an image but not its shape, resulting in what is known as a case 1 real image.
Step-by-step explanation:
The function of a movie projector that enlarges the image on the film is an example of a dilation. A dilation in physics refers to a transformation that changes the size but not the shape of an image. With a movie projector, light rays coming from the film pass through a converging lens system. If the object distance (do) is greater than the focal length (f), and f is positive, a real image is produced, which can be projected onto a screen, this concept is known as case 1 image formation. The real image formed is larger than the object, which means that the magnification is greater than 1. However, in the context of geometric transformations in mathematics, 'dilation' is the correct term to describe an enlargement or reduction of a figure. Therefore, the correct answer to the student's question would be dilation, which is option (4).