ratio of refraction
31industrial glass — Introduction solid material that is normally lustrous and transparent in appearance and that shows great durability under exposure to the natural elements. These three properties lustre, transparency, and durability make glass a favoured… …
32Ibn al-Haytham — Infobox Muslim scholars | notability = Muslim scientist| era = Islamic Golden Age| color = #cef2e0 | | image caption = Ibn al Haytham drawing taken from a 1982 Iraqi 10 dinar note. | | name = Unicode|Abū ‘Alī al Ḥasan ibn al Ḥasan ibn al Haytham… …
33Eyeglass prescription — Using a phoropter to determine a prescription for eyeglasses An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist or ophthalmologist, that specifies the value of all parameters the prescriber has deemed… …
34Taqi al-Din — Muhammad ibn Ma ruf al Shami al Asadi (Arabic: تقي الدين محمد بن معروف الشامي السعدي, Turkish: Takiyuddin) (1526 ndash;1585) was a major Ottoman Turkish [cite journal last = Douglas | first = A. V. year =1963 title = Tenth International Congress… …
35Luminiferous aether — The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century, luminiferous aether or ether, meaning light bearing aether, was the term used to describe a medium for the… …
36Numerical aperture — The numerical aperture with respect to a point P depends on the half angle θ of the maximum cone of light that can enter or exit the lens. In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes… …
37Speed of sound — Sound is a vibration that travels through an elastic medium as a wave. The speed of sound describes how much distance such a wave travels in a certain amount of time. In SI Units with dry air at 20 °C (68 °F), the speed of sound is 343 m/s. This… …
38Slow light — is the literal slowing of the speed of light. It is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. The term is usually only applied when the velocity is at least hundreds of times… …
39characteristic — Index In dex, n.; pl. E. {Indexes}, L. {Indices}(?). [L.: cf. F. index. See {Indicate}, {Diction}.] [1913 Webster] 1. That which points out; that which shows, indicates, manifests, or discloses; as, the increasing unemployment rate is an index of …
40fist — Index In dex, n.; pl. E. {Indexes}, L. {Indices}(?). [L.: cf. F. index. See {Indicate}, {Diction}.] [1913 Webster] 1. That which points out; that which shows, indicates, manifests, or discloses; as, the increasing unemployment rate is an index of …
