What is a convex mirror and what is it used for?

This statement, seen on most side-view mirrors, is a very important safety message—the message warns the driver that the mirror is deceiving. Why would an automobile manufacturer put a deceiving mirror on a car? A flat, plane mirror would only show the driver a small, narrow section of the road behind the car; if, however, a convex mirror is used, the driver can not only see behind the car, but to the side as well, reducing his or her blind spot. In the process, however, convex mirrors make objects appear smaller and therefore farther away, so the message is there to serve as a reminder that the image is not exactly as it appears.

A convex mirror is the opposite of a concave mirror in that it is curved outward. The reflected light spreads out rather than converging at a point. Therefore convex mirrors form virtual images. Convex mirrors are used for security purposes in stores because they broaden the reflected field of vision, allowing clerks to see a large section of the store. The images are smaller than the objects, but the mirrors help to see a wide area.


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