Answers

2014-11-02T19:30:31+05:30
Earlier still or dark water collected in a vessel was considered or used as mirrors by ancient people. Then as days passed obsidian mirrors came in to existence followed by metal coated glass mirrors this led to discovery of metal coated spherical or parabolic mirrors.  A spherical mirror is a mirror which has the shape of a piece cut out of a spherical surface. There are two types of spherical mirrors: concave, and convex. These mirrors are also known as parabolic mirrors discovered in mid9th century Ibn al haytham and Ibn sahl.parabolic mirrors were described in classical antiquity written by mathematician-Diocles . In addition to these researches Ptolemy also carried out experiments with curved polished iron mirrors and discussed about convex spherical and concave spherical mirrors in his book optics.   Inspite of these researches finding the focal length of spherical mirror was a though task but finally Ibn al Hay tham got a break through by finding out the focal length of curved surfaces using the laws of reflection.he stated that “All the reflected rays of a mirror converge or diverge and meet at a point known as focus and the distance between focus and pole of mirror is known as focal point of mirror.’’Also many scientists came to a conclusion that spherical mirrors can be divided into concave and convex mirrors.   Spherical mirrors   Concave mirrors   Convex mirrors The invention of concave and convex mirrors led to many changes and have become a part of our life .



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2014-11-02T19:37:04+05:30
The idea of mirrors came into existencce long back when people saw their images on water and poluted surfaces etc.....
the history of mirrors started in 6000 BC the earlist man made mirrors were pieces poluted stones.
the first glass mirrors were produced in 1 A.D. by romans
the first modren silver glass was created by  justus von liebig a german chemist in 1835.
the invention of glass blowing method during the 14 th century led to th ediscovery of spherical mirrors.which increased the popularity of glass mirrors.
by th e end of 18 th century decorative mirrors are widely used.
new cheaper tchniques of mirrors in the 19 th century led to a great proliferation in their use. now a days wide spreadly using.
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