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29) Republic Day 2020 Parade FEATURES: Colourful tableaux, daredevilry, government might on display

India Republic Day -- India Republic Day 2020 Attend, Flag Hosting HIGHLIGHTS: Prime Minister Narendra Modi paid out his tributes to martyrs by laying a wreath at the National War Memorial in the presence of Defence Minister Rajnath Singh, the 3 service chiefs and Primary of Defence Staff Bipin Rawat. India Republic Day Parade 2020, Flag Internet hosting HIGHLIGHTS: India is drinking its 70th Republic Day Today. The celebration with Rajpath started with Prime Minister Narendra Modi forking over homage to the fallen troops at the newly-built National War Memorial on the Republic Day for the first time instead of the Amar Jawan Jyoti beneath the India Door arch. This was followed by President Ram Nath Kovind unfurling the tricolour. The event marks the day when India’s Constitution came into effect, as well as the country became a republic. Heavylift helicopter Chinook along with attack helicopter Apache, equally recently inducted in the American native indians Air Force, took part i
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X-ray

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An X-ray , or X-radiation , is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (30×1015Hz to 30×1018 Hz) and energies in the range 124 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation , after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it X-radiation to signify an unknown type of radiation. Spellings of X-ray(s) in English include the variants x-ray(s) , xray(s) , and X ray(s) .
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History

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Pre-Röntgen observations and research edit Before their discovery in 1895, X-rays were just a type of unidentified radiation emanating from experimental discharge tubes. They were noticed by scientists investigating cathode rays produced by such tubes, which are energetic electron beams that were first observed in 1869. Many of the early Crookes tubes (invented around 1875) undoubtedly radiated X-rays, because early researchers noticed effects that were attributable to them, as detailed below. Crookes tubes created free electrons by ionization of the residual air in the tube by a high DC voltage of anywhere between a few kilovolts and 100 kV. This voltage accelerated the electrons coming from the cathode to a high enough velocity that they created X-rays when they struck the anode or the glass wall of the tube. The earliest experimenter thought to have (unknowingly) produced X-rays was actuary William Morgan. In 1785 he presented a paper to the Royal Society of London describing the ef
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Energy ranges

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Soft and hard X-rays edit X-rays with high photon energies (above 5–10 keV, below 0.2–0.1 nm wavelength) are called hard X-rays , while those with lower energy (and longer wavelength) are called soft X-rays . Due to their penetrating ability, hard X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. The term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. Since the wavelengths of hard X-rays are similar to the size of atoms, they are also useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air; the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometer. Gamma rays edit There is no consensus for a definition distinguishing between X-rays and gamma rays. One common practice is to distinguish between the two types of radiation based on their source: X-rays are emitted by elec
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Properties

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X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds. This makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a short period of time causes radiation sickness, while lower doses can give an increased risk of radiation-induced cancer. In medical imaging this increased cancer risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in cancer treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy. Hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects. The most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry (e.g. industrial radiography and industrial CT scan
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Interaction with matter

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X-rays interact with matter in three main ways, through photoabsorption, Compton scattering, and Rayleigh scattering. The strength of these interactions depends on the energy of the X-rays and the elemental composition of the material, but not much on chemical properties, since the X-ray photon energy is much higher than chemical binding energies. Photoabsorption or photoelectric absorption is the dominant interaction mechanism in the soft X-ray regime and for the lower hard X-ray energies. At higher energies, Compton scattering dominates. Photoelectric absorption edit The probability of a photoelectric absorption per unit mass is approximately proportional to Z 3/ E 3, where Z is the atomic number and E is the energy of the incident photon. This rule is not valid close to inner shell electron binding energies where there are abrupt changes in interaction probability, so called absorption edges. However, the general trend of high absorption coefficients and thus short penetration dep
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Production

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Whenever charged particles (electrons or ions) of sufficient energy hit a material, X-rays are produced. Production by electrons edit Characteristic X-ray emission lines for some common anode materials. Anode material Atomic number Photon energy keV Wavelength nm K α1 K β1 K α1 K β1 W 74 59.3 67.2 0.0209 0.0184 Mo 42 17.5 19.6 0.0709 0.0632 Cu 29 8.05 8.91 0.154 0.139 Ag 47 22.2 24.9 0.0559 0.0497 Ga 31 9.25 10.26 0.134 0.121 In 49 24.2 27.3 0.0512 0.455 X-rays can be generated by an X-ray tube, a vacuum tube that uses a high voltage to accelerate the electrons released by a hot cathode to a high velocity. The high velocity electrons collide with a metal target, the anode, creating the X-rays. In medical X-ray tubes the target is usually tungsten or a more crack-resistant alloy of rhenium (5%) and tungsten (95%), but sometimes molybdenum for more specialized applications, such as when softer X-rays are needed as in mammography. In c
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