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Henry G. Moseley
Henry Gwyn Jeffreys Moseley (; 23 November 1887 – 10 August 1915) was an English physicist, whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. This stemmed from his development of Moseley's law in X-ray spectra. Moseley's law advanced atomic physics, nuclear physics and quantum physics by providing the first experimental evidence in favour of Niels Bohr's theory, aside from the hydrogen atom spectrum which the Bohr theory was designed to reproduce. That theory refined Ernest Rutherford's and Antonius van den Broek's model, which proposed that the atom contains in its nucleus a number of positive nuclear charges that is equal to its (atomic) number in the periodic table. This remains the accepted model today. When World War I broke out in Western Europe, Moseley left his research work at the University of Oxford behind to volunteer for the Royal Engineers of the British Arm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weymouth, Dorset
Weymouth is a seaside town in Dorset, on the English Channel coast of England. Situated on a sheltered bay at the mouth of the River Wey, south of the county town of Dorchester, Weymouth had a population of 53,427 in 2021. It is the third largest settlement in Dorset after Bournemouth and Poole. The history of the town stretches back to the 12th century and includes roles in the spread of the Black Death, the settlement of the Americas and the development of Georgian architecture. It was a major departure point for the Normandy Landings during World War II. Prior to local government reorganisation in April 2019, Weymouth formed a borough with the neighbouring Isle of Portland. Since then the area has been governed by Dorset Council. Weymouth, Portland and the Purbeck district are in the South Dorset parliamentary constituency. A seaside resort, Weymouth and its economy depend on tourism. Visitors are attracted by its harbour and position, halfway along the Jurassic Coast ... [...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 phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies (also known as applie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Engineers
The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is a corps of the British Army. It provides military engineering and other technical support to the British Armed Forces and is headed by the Chief Royal Engineer. The Regimental Headquarters and the Royal School of Military Engineering are in Chatham in Kent, England. The corps is divided into several regiments, barracked at various places in the United Kingdom and around the world. History The Royal Engineers trace their origins back to the military engineers brought to England by William the Conqueror, specifically Bishop Gundulf of Rochester Cathedral, and claim over 900 years of unbroken service to the crown. Engineers have always served in the armies of the Crown; however, the origins of the modern corps, along with those of the Royal Artillery, lie in the Board of Ordnance established in the 15th century. In Woolwich in 1716, the Board formed the Royal Regime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Oxford
, mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor = The Lord Patten of Barnes , vice_chancellor = Louise Richardson , students = 24,515 (2019) , undergrad = 11,955 , postgrad = 12,010 , other = 541 (2017) , city = Oxford , country = England , coordinates = , campus_type = University town , athletics_affiliations = Blue (university sport) , logo_size = 250px , website = , logo = University of Oxford.svg , colours = Oxford Blue , faculty = 6,995 (2020) , academic_affiliations = , The University of Oxford is a collegiate research university in Oxf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean world, the Roman Empire (Western Roman Empire and Eastern Roman Empire), and medieval "Christendom" (Western Christianity and Eastern Christianity). Beginning with the Renaissance and the Age of Discovery, roughly from the 15th century, the concept of ''Europe'' as "the West" slowly became distinguished from and eventually replaced the dominant use of "Christendom" as the preferred endonym within the region. By the Age of Enlightenment and the Industrial Revolution, the concepts of "Eastern Europe" and "Western Europe" were more regularly used. Historical divisions Classical antiquity and medieval origins Prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. As the Roman domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fighting occurring throughout Europe, the Middle East, Africa, the Pacific, and parts of Asia. An estimated 9 million soldiers were killed in combat, plus another 23 million wounded, while 5 million civilians died as a result of military action, hunger, and disease. Millions more died in genocides within the Ottoman Empire and in the 1918 influenza pandemic, which was exacerbated by the movement of combatants during the war. Prior to 1914, the European great powers were divided between the Triple Entente (comprising France, Russia, and Britain) and the Triple Alliance (containing Germany, Austria-Hungary, and Italy). Tensions in the Balkans came to a head on 28 June 1914, following the assassination of Archduke Franz Ferdin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Charge
In atomic physics, the effective nuclear charge is the actual amount of positive (nuclear) charge experienced by an electron in a multi-electron atom. The term "effective" is used because the shielding effect of negatively charged electrons prevent higher energy electrons from experiencing the full nuclear charge of the nucleus due to the repelling effect of inner layer. The effective nuclear charge experienced by an electron is also called the core charge. It is possible to determine the strength of the nuclear charge by the oxidation number of the atom. Most of the physical and chemical properties of the elements can be explained on the basis of electronic configuration. Consider the behavior of ionization energies in the periodic table. It is known that the magnitude of ionization potential depends upon the following factors: # Size of atom; # The nuclear charge; # The screening effect of the inner shells, and # The extent to which the outermost electron penetrates into the charge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Nucleus
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg. An atom is composed of a positively charged nucleus, with a cloud of negatively charged electrons surrounding it, bound together by electrostatic force. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force. The diameter of the nucleus is in the range of () for hydrogen (the diameter of a single proton) to about for uranium. These dimensions are much smaller than the diameter of the atom itself (nucleus + electron cloud), by a factor of about 26,634 (uranium atomic radiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics, as if they were tennis balls for example, is not possible due to quantum effects. More than 99.94% of an atom's mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, then the atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively – such atoms are called ions. The electrons of an atom are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonius Van Den Broek
Antonius Johannes van den Broek (4 May 1870, Zoetermeer – 25 October 1926, Bilthoven) was a Dutch amateur physicist notable for being the first who realized that the number of an element in the periodic table (now called atomic number) corresponds to the charge of its atomic nucleus. This hypothesis was published in 1911 and inspired the experimental work of Henry Moseley, who found good experimental evidence for it by 1913. Life Van den Broek was the son of a civil law notary and trained to be a lawyer himself. He studied at Leiden University and at the Sorbonne in Paris, obtaining a degree in 1895 in Leiden. From 1895 to 1900 he held a lawyers office in The Hague until 1900, after which he studied mathematical economy in Vienna and Berlin. However, from 1903 on, his main interest was physics. Much of the time between 1903 and 1911 he lived in France and Germany. Most of his papers he wrote between 1913 and 1916 while living in Gorssel. He married Elisabeth Margaretha Mauve in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohr Model
In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity. It came after the solar system Joseph Larmor model (1897), the solar system Jean Perrin model (1901), the cubical model (1902), the Hantaro Nagaoka Saturnian model (1904), the plum pudding model (1904), the quantum Arthur Haas model (1910), the Rutherford model (1911), and the nuclear quantum John William Nicholson model (1912). The improvement over the 1911 Rutherford model mainly concerned the new quantum physical interpretation introduced by Haas and Nicholson, but forsaking any attempt to align with classical physics radiation. The model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen. While the Rydberg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Spectroscopy
X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. Characteristic X-ray spectroscopy When an electron from the inner shell of an atom is excited by the energy of a photon, it moves to a higher energy level. When it returns to the low energy level, the energy which it previously gained by the excitation is emitted as a photon which has a wavelength that is characteristic for the element (there could be several characteristic wavelengths per element). Analysis of the X-ray emission spectrum produces qualitative results about the elemental composition of the specimen. Comparison of the specimen's spectrum with the spectra of samples of known composition produces quantitative results (after some mathematical corrections for absorption, fluorescence and atomic number). Atoms can be excited by a high-energy beam of charged particles such as electrons (in an electron microscope for example), protons (se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
