Convex Mirrors, rays, and image

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The importance of understanding convex mirrors, the rays, and images that they produce.

History of Mirrors (Convex)
The convex mirror has gone in and out of style since the Eighteenth Century, when glassmakers in Louis XIV’s France figured out how to press plate glass into large flat mirrors (making possible the famous Hall of Mirrors at Versailles). The history of mirrors dates back to ancient times when mankind first saw reflections in a pond or river and considered it magic. Polished stone or metal was used in the first early man-made mirrors. Later glass was used in combination with metals like tin, mercury, and leads to create mirrors. The definition of a mirror is a reflecting surface that forms an image of an object when light rays coming from that object fall upon the surface. Today, combining glass and metal is still the design used in almost all modern mirrors. Mirrors made by coating flat glass with silver or gold foil dates from Roman times and the inventor are unknown. A convex mirror looks like an upside-down bowl, in a convex mirror objects look bigger in the center. Jan van Eyck’s famous 1434 Arnolfini portrait contains the first known image of a convex mirror, included in part to show off the technical skill it took to reproduce the distorted reflection .A convex mirror is a reflecting surface that represents a segment of the outer surface of a sphere. Technically, convex mirrors are negative mirrors because their reflective surfaces face away from the center of the sphere. Images formed by mirrors are called virtual images and appear to originate from a point behind the mirror or to be trapped inside the mirror. Convex mirror images are always upright and always smaller than the actual objects. These properties make convex mirrors useful on vehicles and in places such as stores where they are used to view customer activity.
Topic Description
Determine the location of an image formed by a convex mirror by using the "mirror equation," which relates object distance (D object), image distance (D image), and focal length (F) of the mirror as follows: The focal length is the distance between the mirror and the point where rays of light emanating from an object converge. You will need to know the value of F in order to locate images formed by a mirror. Determine the height of an image by using the "mirror magnification relation," which relates image height (H image), object height (H object), image distance (D image) and object distance (D object) as follows: M = (H image)/(H object) = (D image)/(D object). Convex mirrors and their images play an important role in order to provide safe. These mirrors are often placed at places where the regular eye can not see. It also make images appear closer so you can see things before they are right up on you.
Application of Convex Mirrors
Convex mirrors seem to have served the expected decorative function of adding light and reflection to interiors. Painters would also use the convex mirror as a tool of perspective. Large hospitals, stores and office buildings often use convex mirrors to allow people to see what is around a corner to help keep people from running into one another. Convex mirrors are used to make sunglass lenses. These mirrors help reflect some of the sunlight away from the wearer's eyes. Two convex mirrors placed back to back are used to make a magnifying glass. Convex mirrors are often placed near ATMs to allow bank customers to see if someone is behind them. This is a security measure that helps keep ATM users safe from robbery of any cash withdrawals and helps keep ATM users' identity more secure. Convex mirrors have many applications, for safety, security, extra visibility-many applications. They can be obvious, or not noticeable, but it would be difficult in some situations to be without them.


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References

  1. Beiser, A. (1988). Physical Science (2nd Edition). New York, NY: McGraw Hill
  2. http://inventors.about.com/od/gstartinventions/a/glass_2.html
  3. Smith, M. (1996). Ptolemy's theory of visual perception: an English translation of the Optics. American Philosophical Society, Science

This WikiPage developed by: Demario Long - 2012SP