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A mirror reflecting the image of a vase A first-surface mirror coated with aluminium and enhanced with dielectric coatings. The angle of the incident light (represented by both the light in the mirror and the shadow behind it) exactly matches the angle of reflection (the reflected light shining on the table). 4.5-metre (15 ft)-tall acoustic mirror near Kilnsea Grange, East Yorkshire, UK, from ...
A concave mirror, or converging mirror, has a reflecting surface that is recessed inward (away from the incident light). Concave mirrors reflect light inward to one focal point. They are used to focus light. Unlike convex mirrors, concave mirrors show different image types depending on the distance between the object and the mirror.
Plane mirrors are the only type of mirror for which an object produces an image that is virtual, erect and of the same size as the object in all cases irrespective of the shape, size and distance from mirror of the object however same is possible for other types of mirror (concave and convex) but only for a specific conditions.
The primary mirror in most modern telescopes is composed of a solid glass cylinder whose front surface has been ground to a spherical or parabolic shape. A thin layer of aluminum is vacuum deposited onto the mirror, forming a highly reflective first surface mirror. Some telescopes use primary mirrors which are made differently.
In the early 10th century, the Persian scientist al-Razi described ways of silvering and gilding in a book on alchemy, [citation needed] but this was not done for the purpose of making mirrors. Tin-coated mirrors were first made in Europe in the 15th century. The thin tinfoil used to silver mirrors was known as "tain". [5]
The use of the mirror resulted in the measured angle being twice the angle included by the index and the radius arm. The mirror on the radial arm was small enough that the observer could see the reflection of an object in half the telescope's view while seeing straight ahead in the other half. This allowed the observer to see both objects at once.
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Principle of the periscope. The periscope on the left uses mirrors whereas the right uses prisms. a Mirrors b Prisms c Observer's eye Principle of the lens periscope. The two periscopes differ in the way they erect the image. The left one uses an erecting prism whereas the right uses an erecting lens and a second image plane. a Objective lens b ...