Search results
Results from the WOW.Com Content Network
Luminiferous aether or ether[ 1 ] (luminiferous meaning 'light-bearing') was the postulated medium for the propagation of light. [ 2 ] It was invoked to explain the ability of the apparently wave -based light to propagate through empty space (a vacuum), something that waves should not be able to do. The assumption of a spatial plenum (space ...
Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants. Indoor lighting is usually accomplished using light fixtures, and is a key part of interior design. Lighting can also be an intrinsic component of landscape projects.
History of optics. Modern ophthalmic lens making machine. Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The word optics is derived from the Greek term ...
The 26th General Conference on Weights and Measures (CGPM) redefined the candela in 2018. [10] [11] The new definition, which took effect on 20 May 2019, is: The candela [...] is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10 12 Hz, [a] K cd, to be 683 when expressed in the unit lm W −1, which is equal to cd sr W −1 ...
Nonlinear optics. Structure of KTP crystal, viewed down b axis, used in second harmonic generation. Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization density P responds non-linearly to the electric field E of the light.
Sir Joseph Wilson Swan FRS (31 October 1828 – 27 May 1914) was an English physicist, chemist, and inventor.He is known as an independent early developer of a successful incandescent light bulb, and is the person responsible for developing and supplying the first incandescent lights used to illuminate homes and public buildings, including the Savoy Theatre, London, in 1881.
Ole Rømer. Ole Christensen Rømer (Danish: [ˈoːlə ˈʁœˀmɐ]; 25 September 1644 – 19 September 1710) was a Danish astronomer who, in 1676, first demonstrated that light travels at a finite speed. Rømer also invented the modern thermometer showing the temperature between two fixed points, namely the points at which water respectively ...
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. [1] It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle. The procedure for conversion from spectral radiance to luminance is ...