د "هينداره" د بڼو تر مېنځ توپير

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Xqbot (خبرې اترې | ونډې)
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۱ کرښه:
[[imageدوتنه:Mirror.jpg|frame|left|A mirror, reflecting a [[vase]].]]
'''هينداره''' is an object with a surface that has good [[specular reflection]]; that is, it is smooth enough to form an [[image]]. The most familiar type of mirror is the ''[[Plane (mathematics)|plane]] mirror'', which has a flat surface. [[Curved mirror]]s are also used, to produce [[magnification|magnified]] or demagnified images or focus light.
 
Mirrors are most commonly used for personal grooming, decoration, and architecture. Mirrors are also used in scientific apparatus such as [[telescope]]s and [[laser]]s, Cameras, and industrial machinery. Most mirrors are designed for [[visible light]], however, mirrors designed for other [[wavelength]]s of [[electromagnetic radiation]] are also used, especially in optical [[#Instruments|instruments]].
 
== اغېزې ==
[[Imageدوتنه:Waves_reflecting_from_a_curved_mirror.PNG|frame|right|In this diagram plain mirror waves reflect off a parabolic mirror to form waves converging onto a focal point.]]
 
In a plane mirror, a [[parallel (geometry)|parallel]] beam of [[light]] changes its direction as a whole, while still remaining parallel; the images formed by a plane mirror are [[virtual image]]s, of the same size as the original object (see [[mirror image]]). There are also [[concave mirror]]s, where a parallel beam of light becomes a [[Convergence|convergent]] beam, whose rays intersect in the [[Focus (optics)|focus]] of the mirror. Lastly, there are [[convex mirror]]s, where a parallel beam becomes divergent, with the [[ray (optics)|rays]] appearing to diverge from a common intersection "behind" the mirror. Spherical concave and convex mirrors do not focus parallel rays to a single point due to [[spherical aberration]]. However, the ideal of focusing to a point is a commonly-used approximation. [[Parabolic reflector]]s resolve this, allowing incoming parallel rays (for example, light from a distant star) to be focused to a small spot; almost an ideal point. Parabolic reflectors are not suitable for imaging nearby objects because the light rays are not parallel.
 
A beam of light reflects off a mirror at an angle of reflection that is equal to its angle of incidence (if the size of a mirror is much larger than the wavelength of light). That is, if the beam of light is shining on a mirror's surface at a 30° angle from vertical, then it reflects from the point of incidence at a 30° angle from vertical in the opposite direction.
۱۵ کرښه:
{{seealso|Mirror image}}
 
== Composition ==
Early mirrors were often little more than a sheet of polished [[metal]], often [[silver]] or [[copper]], for example the [[Aranmula kannadi]]. Most modern mirrors consist of a thin layer of [[aluminium]] deposited on a sheet of [[glass]]. This layer is called the Tain. They are [[silvering|back silvered]], where the reflecting surface is viewed through the glass sheet; this makes the mirror durable, but lowers the image quality of the mirror due to extraneous reflections from the front surface of the glass (ordinary glass typically reflects around 4% of the light). This type of mirror reflects about 80% of the incident light. The "back side" of the mirror is often painted or coated in some way to completely seal the metal from [[corrosion]].
 
۲۲ کرښه:
Mirrors designed for special applications, such as in [[LASER]]s and other advanced optical devices, use a reflective [[optical coating]] composed of many layers of different [[dielectric]] materials. Such coatings can be designed to have extremely high reflectivity and are reasonably durable. Since they absorb very little of the incident light they can be used with high power lasers without absorbing the energy and being damaged.
 
== Applications ==
[[imageدوتنه:mirror.globe.arp.500pix.jpg|thumb|right|200px|Reflections in a spherical convex mirror. The photographer is seen at top right]]
 
 
==== Safety and easier viewing ====
[[Rear-view mirror]]s are used in and on [[vehicle]]s (such as [[automobile]]s, or [[bicycles]]), to allow drivers to see other vehicles coming up behind them. Some [[motorcycle helmet]]s have a built-in so-called MROS (Multiple Reflective Optic System): a set of reflective surfaces inside the helmet which together function as a rear-view mirror.[http://www.reevu.nl] There exist rear view [[sunglasses]], of which the left end of the left glass and the right end of the right glass work as mirrors.
 
۳۵ کرښه:
With the [[sun]] as light source, a mirror can be used to signal, by variations in the orientation of the mirror. The signal can be used over long distances, possibly up to 60 [[kilometre]]s on a clear day. This technique was used by [[Indigenous peoples of the Americas|Native American]] tribes and numerous [[military|militaries]] to transmit information between distant outposts.
 
==== One-way mirror ====
A ''one-way mirror'' reflects some percentage of the light and lets some other percentage pass. It is a sheet of glass coated with a layer of metal only a few dozen atoms thick, allowing some of the light through the surface (from both sides). It is used between a dark room and a brightly lit room. Persons on the brightly lit side see their own reflection - it looks like a normal mirror. Persons on the dark side see through it - it looks like a [[transparency (optics)|transparent]] window. It may be used to observe criminal suspects or customers (to watch out for theft). The same type of mirror, when used in an [[optical instrument]], is called a ''half-silvered mirror'' or [[beam splitter]]. Its purpose is to split a beam of light so that half passes straight through, while the other half is reflected — this is useful for [[interferometry]].
 
Contrary to popular belief, one-way mirrors that function well between equally lit rooms do not exist. The laws of physics do not allow for real, passive one-way mirrors (ones that do not need external energy); if such a device were possible, one could break the [[second law of thermodynamics]] and make energy flow from a cold object to a hot one, by placing such a mirror between them. (There is no prohibition against one-way ''windows'', however.<ref>{{cite web|url=http://www.usna.edu/Users/physics/mungan/Scholarship/FaradayIsolators.pdf |title=Faraday Isolators and Kirchhoff’s Law: A Puzzle |accessdate=2006-07-18 |last=Mungan |first=C.E. |year=1999 |format=pdf}}</ref><ref>Rayleigh, ''On the magnetic rotation of light and the second law of thermodynamics'', Nature (London), Vol. '''64''', p. 577 (Oct. 10, 1901).</ref> [[Faraday isolator|Optical isolatorisolators]]s are one-way devices, that are commonly used with [[laser]]s.)
 
=== Technology ===
==== Televisions and Projectors ====
Microscopic mirrors are a core element of many of the largest [[HDTV|high-definition]] [[televisions]] and video [[projectors]]. A common technology of this type is [[Texas Instruments]]' [[DLP]]. A DLP chip is a postage stamp-sized microchip whose surface is comprised of an array of millions of microscopic mirrors. The picture is created as the individual mirrors move to either reflect light toward the projection surface ([[pixel]] on), or toward a light absorbing surface (pixel off).
 
Other projection technologies involving mirrors include [[LCoS]]. Like a DLP chip, LCoS is a microchip of similar size, but rather than millions of individual mirrors, there is a single mirror that is actively shielded by a [[liquid crystal]] [[matrix]] with up to millions of [[pixels]]. The picture is formed as light is either reflected toward the projection surface (pixel on), or absorbed by the activated [[LCD|LCD]] pixels (pixel off). LCoS-based televisions and projectors often use 3 chips, one for each primary color.
 
==== Instruments ====
[[Telescope]]s and other precision instruments use ''front silvered'' or ''first surface'' mirrors, where the reflecting surface is placed on the front (or first) surface of the glass (this eliminates reflection from glass surface ordinary back mirrors have). Some of them use silver, but most are aluminum, which is more reflective at short wavelengths than silver.
All of these coatings are easily damaged and require special handling.
۶۵ کرښه:
A [[Mangin mirror]] is a combination lens and concave mirror and is widely used in optical instruments and even sometimes in cameras.[http://www.jmloptical.com/level2/ProductInfo/m_spherical_info.aspx] [http://www.aavso.org/publications/ejaavso/ej14.pdf][http://www.bobatkins.com/photography/tutorials/mirror.html]
 
==== Military Applications ====
It has been said that [[Archimedes]] used a large array of mirrors to burn [[Ancient Rome|Roman]] ships during an attack on Syracuse. This has never been proven or disproved; however, many have put it to the test. Recently, on a popular [[Discovery Channel]] show, [[MythBusters]], a team from [[MIT]] tried to recreate the famous "Archimedes Death Ray". They were [http://web.mit.edu/2.009/www/lectures/10_Mythbusters.html successful] at starting a fire on a ship at 75 feet away, however, previous attempts to light the boat on fire using only the bronze mirrors available in Archimedes' time were unsuccessful, and the time taken to ignite the craft would have made its use impractical, resulting in the MythBusters team deeming the myth implausible.
 
Modern [[Nuclear weapon|thermonuclear weapons]] use x-ray mirrors to focus radiation from the primary onto the secondary to create conditions favoring nuclear fusion ''(see [[Nuclear weapons design]] for more details)''.
 
[[Imageدوتنه:Teller-Ulam device firing sequence.png|center|frame|Application of x-ray mirrors in a thermonuclear weapon.]]
 
==== Seasonal lighting ====
 
<!-- If this technique becomes popular, don't let this section grow into a vast list of examples. -->
Due to its location in a steep-sided valley, the Italian town of [[Viganella]] gets no direct sunlight for 6 weeks each winter. In 2006 a &euro;100€100,000 computer-controlled mirror, 8&nbsp;m &times;× 5&nbsp;m, was installed to reflect sunlight into the town's piazza. In early 2007 the similarly situated village of [[Bondo, Switzerland]], was considering applying this solution as well.<ref>http://news.bbc.co.uk/2/hi/europe/6189371.stm</ref><ref>http://www.cbsnews.com/stories/2007/02/12/ap/world/mainD8N8AED80.shtml</ref>
 
=== Leisure ===
==== Decoration ====
Mirrors, typically large and unframed, are frequently used in [[interior decoration]] to create an illusion of space, and amplify the apparent size of a room.
 
۸۵ کرښه:
A decorative reflecting [[sphere]] of thin metal-coated glass, working as a reducing wide-angle mirror, is sold as a [[Christmas ornament]] called a ''bauble''.
 
==== Entertainment ====
The [[house of mirrors|hall of mirrors]], commonly found in [[amusement park]]s, is an attraction in which a number of distorted mirrors are used to produce unusual reflections of the visitor. Mirror mazes, also found in [[amusement park]]s, contain large numbers of mirrors and sheets of glass. The idea is to navigate the disorientating array without bumping into the walls.
 
۹۴ کرښه:
Mirrors are employed in [[kaleidoscope]]s, personal entertainment devices invented in [[Scotland]] by sir [[David Brewster]].
 
==== Anamorphosis ====
One kind of [[anamorphosis]] has an interposed cylindrical or conical mirror making it possible to apprehend an image which is the reflection of a deformed image conceived for this purpose. The deformed image is painted on a plane surface surrounding the mirror. By looking uniquely into the mirror, the image appears normal.
 
== Mirrors in literature ==
[[imageدوتنه:A girl looking at herself in the mirror.jpg|thumb|right|250px|A girl looking in the mirror]]
It is a common [[superstition]] that someone who breaks a mirror will receive seven years of bad luck.
 
۱۴۳ کرښه:
In Chinese Literature, the novel [[Dream of the Red Chamber]], a Taoist monk has a two sided mirror that is capable of reflecting truth from the main screen, while the back screen shows the distorted truth.
 
== See also ==
*[[Anamorphosis]]
*[[Aranmula kannadi]]
۱۵۸ کرښه:
*[[Venus effect]]
*[[Deformable mirror]]
== Notes ==
{{reflist}}
 
== Bibliography ==
*''Mirror, Mirror: A History of the Human Love Affair with Reflection'', Mark Pendergrast. Basic Books (2003). ISBN 0-465-05471-4 .
*''On reflection'', Jonathan Miller. National Gallery Publications Limited (1998). ISBN 0-300-07713-0 .
 
== External links ==
 
* [http://vision2form.nl/mirror_history.html History of mirrors and glass]
* [http://yvesdore.com/mirror.html The Narcissus Syndrome Revisited by Yves Doré]
 
[[Categoryوېشنيزه:Mirrors| ]]
 
[[ar:مرآة]]
۲۰۸ کرښه:
[[no:Speil]]
[[nrm:Mireus]]
[[oc:Miralh]]
[[pl:Lustro]]
[[pt:Espelho]]