Final answer:
Convex mirrors are used as car driving mirrors to provide a wider field of view, although they make objects appear smaller and can make judging distances more difficult.
Step-by-step explanation:
Convex mirrors, also known as diverging mirrors, are commonly used as car driving mirrors because they provide a wider field of view. This is the primary reason they are favored over flat mirrors for this application. When light rays hit a convex mirror, they are reflected outward, causing the mirror to display images of objects that are smaller than they would appear in a flat mirror. However, this smaller size allows for a much wider area to be observed, which is vital for driving as it enables the driver to see more of the area behind and to the sides of the vehicle. The main disadvantage of using a convex mirror compared with a flat mirror is that the objects appear smaller, and thus distances can be harder to judge accurately.