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Fresnel Equations - Reflectance
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular theory, from the late 1830s until the end of the 19th century. He is perhaps better known for inventing the catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of "stepped" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler dioptric (purely refractive) stepped lens, first proposed by Count Buffon and independently reinvented by Fresnel, is used in screen magnifiers and in condenser lenses for overhead projectors. By expressing Huygens's principle of secondary waves and Young's principle of interference in quantitative terms, and supposing that simple colors consist of sinusoidal waves, Fresnel gave the first satisfactory explanation of diffraction by straight edges, incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broglie, Eure
Broglie () is a commune in the Eure department in Normandy in northern France. Geography The commune along with another 69 communes shares part of a 4,747 hectare, Natura 2000 conservation area, called Risle, Guiel, Charentonne. Population Notable person * Augustin-Jean Fresnel (1788–1827), physicist, was born in Broglie See also *Communes of the Eure department The following is a list of the 585 communes of the Eure department of France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French G ... References Communes of Eure {{Bernay-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Number
In optics, in particular scalar diffraction theory, the Fresnel number (), named after the physicist Augustin-Jean Fresnel, is a dimensionless number relating to the pattern a beam of light forms on a surface when projected through an aperture. Definition For an electromagnetic wave passing through an aperture and hitting a screen, the Fresnel number ''F'' is defined as : F = \frac where : a is the characteristic size (e.g. radius) of the aperture : L is the distance of the screen from the aperture : \lambda is the incident wavelength. Conceptually, it is the number of half- period zones in the wavefront amplitude, counted from the center to the edge of the aperture, as seen from the observation point (the center of the imaging screen), where a half-period zone is defined so that the wavefront phase changes by \pi when moving from one half-period zone to the next. An equivalent definition is that the Fresnel number is the difference, expressed in half-wavelengths, between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Webster's New World College Dictionary
''Webster's New World Dictionary of the American Language'' is an American dictionary published first in 1951. As of 2022, the work is owned by HarperCollins Publishers. Overview The first edition was published by the World Publishing Company of Cleveland, Ohio, in two volumes or one large volume, including a large encyclopedic section. In 1953, World published a one-volume college edition (''Webster's New World College Dictionary''), without the encyclopedic material. It was edited by Joseph H. Friend and David B. Guralnik and contained 142,000 entries, said to be the largest American desk dictionary available at the time. The second college edition, edited by Guralnik, was published in 1970. World Publishing was acquired by Simon & Schuster in 1980 and they continued the work with a third edition in 1989 edited by Victoria Neufeldt. A fourth edition was edited by Michael Agnes and published by John Wiley & Sons in 1999, containing 160,000 entries; a fifth, edited by Andrew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collins English Dictionary
The ''Collins English Dictionary'' is a printed and online dictionary of English. It is published by HarperCollins in Glasgow. It was first published in 1979. Corpus The dictionary uses language research based on the Collins Corpus, which is continually updated and has over 20 billion words. Editions * The current edition is the 14th; it was published on 31 August 2023, with more than 732,000 words, meanings, and phrases (not 730,000 headwords) and 9,500 place names and 7,300 biographies. A newer edition of the 14th edition was published 7 May 2024. * The previous edition was the 13th edition, which was published in November 2018. * A special "30th Anniversary" 10th edition was published in 2010. * Earlier editions were published once every 3 or 4 years. History The 1979 edition of the dictionary, with Patrick Hanks as editor and Laurence Urdang as editorial director, was the first British English dictionary to be typeset from the output from a computer database in a specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rumford Medal
The Rumford Medal is an award bestowed by the Royal Society for "outstanding contributions in the field of physics". The award is named in honour of British scientist Sir Benjamin Thompson, Count Rumford, who is noted for his works on thermodynamics and for establishing the Royal Institution. The award was created in 1796 after Thompson transferred £1,000 to the Royal Society in stocks, instructing the latter to grant the awardee the fund's interest as a premium. Thompson was awarded the inaugural award in 1800. The award initially consisted of two medals, one each in silver and gold, struck in the same die. This was later replaced with a single medal made of silver gilt. The medal is awarded with a cash prize of £2,000. British painter Robert Smirke created the original design of the medal. The diameter of the medal is 3 inches (7.62 cm). The obverse featured a tripod altar with a flame upon it, circumscribed by a Latin inscription from Lucretius' poem ''De rerum natura'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fellow Of The Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, including mathematics, engineering science, and medical science". Overview Fellowship of the Society, the oldest known scientific academy in continuous existence, is a significant honour. It has been awarded to :Fellows of the Royal Society, around 8,000 fellows, including eminent scientists Isaac Newton (1672), Benjamin Franklin (1756), Charles Babbage (1816), Michael Faraday (1824), Charles Darwin (1839), Ernest Rutherford (1903), Srinivasa Ramanujan (1918), Jagadish Chandra Bose (1920), Albert Einstein (1921), Paul Dirac (1930), Subrahmanyan Chandrasekhar (1944), Prasanta Chandra Mahalanobis (1945), Dorothy Hodgkin (1947), Alan Turing (1951), Lise Meitner (1955), Satyendra Nath Bose (1958), and Francis Crick (1959). More recently, fellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Legion Of Honour
The National Order of the Legion of Honour ( ), formerly the Imperial Order of the Legion of Honour (), is the highest and most prestigious French national order of merit, both military and Civil society, civil. Currently consisting of five classes, it was originally established in 1802 by Napoleon, Napoleon Bonaparte, and it has been retained (with occasional slight alterations) by all later French governments and regimes. The order's motto is ' ("Honour and Fatherland"); its Seat (legal entity), seat is the Palais de la Légion d'Honneur next to the Musée d'Orsay, on the left bank of the Seine in Paris. Since 1 February 2023, the Order's grand chancellor has been retired General François Lecointre, who succeeded fellow retired General Benoît Puga in office. The order is divided into five degrees of increasing distinction: ' (Knight), ' (Officer), ' (Commander (order), Commander), ' (Grand Officer) and ' (Grand Cross). History Consulate During the French Revolution, all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Academy Of Sciences
The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefront of scientific developments in Europe in the 17th and 18th centuries, and is one of the earliest Academy of Sciences, Academies of Sciences. Currently headed by Patrick Flandrin (President of the academy), it is one of the five Academies of the . __TOC__ History The Academy of Sciences traces its origin to Colbert's plan to create a general academy. He chose a small group of scholars who met on 22 December 1666 in the King's library, near the present-day Bibliothèque nationale de France, Bibliothèque Nationale, and thereafter held twice-weekly working meetings there in the two rooms assigned to the group. The first 30 years of the academy's existence were relatively informal, since no statutes had as yet been laid down for the ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Optics
In physics, physical optics, or wave optics, is the branch of optics that studies Interference (wave propagation), interference, diffraction, Polarization (waves), polarization, and other phenomena for which the ray approximation of geometric optics is not valid. This usage tends not to include effects such as quantum noise in optical communication, which is studied in the sub-branch of coherence theory (optics), coherence theory. Principle ''Physical optics'' is also the name of an approximation commonly used in optics, electrical engineering and applied physics. In this context, it is an intermediate method between geometric optics, which ignores wave effects, and full wave electromagnetism, which is a precise theory. The word "physical" means that it is more physical than geometric or ray (optics), ray optics and not that it is an exact physical theory. This approximation consists of using ray optics to estimate the field on a surface and then integral, integrating that field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarization (waves)
, or , is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. One example of a polarized transverse wave is vibrations traveling along a taut string, for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves ( shear waves) in solids. An electromagnetic wave such as light consists of a coupled oscillating el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phasor
In physics and engineering, a phasor (a portmanteau of phase vector) is a complex number representing a sinusoidal function whose amplitude and initial phase are time-invariant and whose angular frequency is fixed. It is related to a more general concept called analytic representation,Bracewell, Ron. ''The Fourier Transform and Its Applications''. McGraw-Hill, 1965. p269 which decomposes a sinusoid into the product of a complex constant and a factor depending on time and frequency. The complex constant, which depends on amplitude and phase, is known as a phasor, or complex amplitude, and (in older texts) sinor or even complexor. A common application is in the steady-state analysis of an electrical network powered by time varying current where all signals are assumed to be sinusoidal with a common frequency. Phasor representation allows the analyst to represent the amplitude and phase of the signal using a single complex number. The only difference in their analytic rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
