2006-09-08 18:07:50 · 6 answers · asked by Don 1 in Science & Mathematics ➔ Physics
Who are we?
Silver was the first, now many materials are used.
2006-09-08 18:11:18 · answer #1 · answered by ppellet 3 · 0⤊ 0⤋
Early mirrors were usually a sheet of polished metal, often silver or copper, for example the Aranmula kannadi.
Most modern mirrors consist of a thin layer of aluminum deposited on a sheet of glass. They are 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. This type of mirror reflects about 80% of the incident light. The "back side" of the mirror is often painted black to completely seal the metal from corrosion.
Mirrors for precision optical applications are more likely to have the reflective coating on the front surface of the mirror, to improve the image quality. Metal films on the front surface are generally covered with a thin, transparent coating (often silica) to protect them from corrosion. In some cases, this coating may be designed to enhance the reflectivity as well.
Mirrors designed for special applications, such as in lasers 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 being damaged by the intense beam
2006-09-09 01:27:11 · answer #2 · answered by Papucho 2 · 0⤊ 0⤋
I think originally mirrors were made with a mercury coating on the back and it was called Quicksilver, that magical, liquid metal, that can cure stuff (which is a totally opposite). Then, they started using silver, but it was too expensive so now they probly use zinc or nickel.
And I didn't know that there is a percentage to how much a mirror reflects. do you mean like light?? or the image itself (which i suppose is the same thing)?
Shouldn't it be 100% unless there is somesort of light filter on the mirror? Colored glass? that would block or dull down the amount of light reflected?
2006-09-09 01:19:06 · answer #3 · answered by ~*Prodigious*~ 3 · 0⤊ 0⤋
The best reflective mirrors are manufactured for use in telescopes, and the reflective material is made of silver, and extremely vulnerable to scratches. As far as actual "percentage" of reflection, in a telescope I would have to say that it's 100% or very near it...otherwise it would be worthless. If there is any protective coating over the back-side of the Silver, it is acrylic
2006-09-09 01:37:19 · answer #4 · answered by LARRY M 3 · 0⤊ 0⤋
If its a concave or convex mirror it messes with the percentages.
however, for a flat household mirror it is as follows: it depends on how far back you are from the mirror. if you are twenty feet back versus two feet back, the image will always be smaller. if you want to know the exact proportion at a given distance, you need to use the pythagorean theorem
2006-09-09 03:28:09 · answer #5 · answered by Double Century Dude 3 · 0⤊ 0⤋
about 70 to 80 %.
2006-09-09 01:42:13 · answer #6 · answered by dwarf 3 · 0⤊ 0⤋