Mirror

A mirror is a reflective surface that is smooth enough to be able to form an image. The best known example is the plane mirror that most people have at home. In it, a parallel beam of light changes its direction as a whole, still beeing parallel; the images formed by a plane mirror are virtual images, of the same size of the object. There are also concave mirrors, where a parallel beam of light becomes a convergent beam, whose rays intersect in the focus? of the mirror. Finally, there are covex mirrors, where a parallel beam becomes divergent, with the apparent intersection ocurring behind the mirror.

Early mirrors consisted of a plate or sheet of polished metal, often silver when the reflected image was for viewing (such as for personal grooming) but also of other metals when only the intensity of reflected light was important.

Modern mirrors usually consist of a thin layer of aluminum deposited on a sheet of glass.