|
Incandescent
Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. The emission of energy arises from a combination of electronic, molecular, and lattice oscillations in a material. Kinetic energy is converted to electromagnetism due to charge-acceleration or dipole oscillation. At room temperature, most of the emission is in the infrared (IR) spectrum, though above around 525 °C (977 °F) enough of it becomes visible for the matter to visibly glow. This visible glow is called incandescence. Thermal radiation is one of the fundamental mechanisms of heat transfer, along with conduction and convection. The primary method by which the Sun transfers heat to the Earth is thermal radiation. This energy is partially absorbed and scattered in the atmosphere, the latter process being the reason why the sky is visibly blue. Much of the Sun's radiation transmit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planck's Law
In physics, Planck's law (also Planck radiation law) describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature , when there is no net flow of matter or energy between the body and its environment. At the end of the 19th century, physicists were unable to explain why the observed spectrum of black-body radiation, which by then had been accurately measured, diverged significantly at higher frequencies from that predicted by existing theories. In 1900, German physicist Max Planck heuristically derived a formula for the observed spectrum by assuming that a hypothetical electrically charged oscillator in a cavity that contained black-body radiation could only change its energy in a minimal increment, , that was proportional to the frequency of its associated electromagnetic wave. While Planck originally regarded the hypothesis of dividing energy into increments as a mathematical artifice, introduced merely to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making up a substance. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), with the third being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wien's Displacement Law
In physics, Wien's displacement law states that the black-body radiation curve for different temperatures will peak at different wavelengths that are inversely proportional to the temperature. The shift of that peak is a direct consequence of the Planck's law, Planck radiation law, which describes the spectral brightness or intensity of black-body radiation as a function of wavelength at any given temperature. However, it had been discovered by German physicist Wilhelm Wien several years before Max Planck developed that more general equation, and describes the entire shift of the spectrum of black-body radiation toward shorter wavelengths as temperature increases. Formally, the wavelength version of Wien's displacement law states that the Radiant flux#units, spectral radiance of black-body radiation per unit wavelength, peaks at the wavelength \lambda_\text given by: \lambda_\text = \frac where is the absolute temperature and is a proportionality constant, constant of proport ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Metalwork
Hot commonly refers refer to: *Heat, a hot temperature *Pungency, in food, a spicy or hot quality Hot or HOT may also refer to: Places *Hot district, a district of Chiang Mai province, Thailand **Hot subdistrict, a sub-district of Hot District, Thailand **Tha Kham, Chiang Mai, also known as Hot, a town in Hot District, Chiang Mai province, Thailand *Hot, Albania, a village in the Malësi e Madhe municipality, Shkodër County, Albania Music *H.O.T. pronounced "H. O. T.", (High-Five of Teenagers), a South Korean boy band *Hawaii Opera Theatre, an opera company in Honolulu, Hawaii *Hot (American vocal group), best known for 1977 hit "Angel in Your Arms" 1976–1980 Albums *Hot (James Brown album), ''Hot'' (James Brown album) or the title song (see below), 1976 *Hot (Freda Payne album), ''Hot'' (Freda Payne album), 1979 *Hot (Paul Bley album), ''Hot'' (Paul Bley album), 1985 *Hot (Half Japanese album), ''Hot'' (Half Japanese album), 1995 *Hot (Squirrel Nut Zippers album), ''Hot'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Camera
Infrared thermography (IRT), thermal video or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared imaging science. Thermographic cameras usually detect radiation in the long-infrared range of the electromagnetic spectrum (roughly 9,000–14,000 nanometers or 9–14 μm) and produce images of that radiation, called thermograms. Since infrared radiation is emitted by all objects with a temperature above absolute zero according to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom
Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper. Atoms with the same number of protons but a different number of neutrons are called isotopes of the same element. Atoms are extremely small, typically around 100 picometers across. A human hair is about a million carbon atoms wide. Atoms are smaller than the shortest wavelength of visible light, which means humans cannot see atoms with conventional microscopes. They are so small that accurately predicting their behavior using classical physics is not possible due to quantum mechanics, quantum effects. More than 99.94% of an atom's mass is in the nucleus. Protons hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Energy
In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic and gravitational radiation. As energy, its SI unit is the joule (J). The quantity of radiant energy may be calculated by integrating radiant flux (or power) with respect to time. The symbol ''Q''e is often used throughout literature to denote radiant energy ("e" for "energetic", to avoid confusion with photometric quantities). In branches of physics other than radiometry, electromagnetic energy is referred to using ''E'' or ''W''. The term is used particularly when electromagnetic radiation is emitted by a source into the surrounding environment. This radiation may be visible or invisible to the human eye. Terminology use and history The term "radiant energy" is most commonly used in the fields of radiometry, solar energy, heating and lighting, but is also sometimes used in other fields (such as telecommunications). In modern applications involving transmission of power fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Energy
The term "thermal energy" is often used ambiguously in physics and engineering. It can denote several different physical concepts, including: * Internal energy: The energy contained within a body of matter or radiation, excluding the potential energy of the whole system. * Heat: Energy in transfer between a system and its surroundings by mechanisms other than Work (thermodynamics), thermodynamic work and transfer of matter. * The characteristic energy kT (energy), associated with a single microscopic degree of freedom, where denotes temperature and denotes the Boltzmann constant. Mark Zemansky (1970) has argued that the term "thermal energy" is best avoided due to its ambiguity. He suggests using more precise terms such as "internal energy" and "heat" to avoid confusion. The term is, however, used in some textbooks.For example: Relation between heat and internal energy In thermodynamics, heat is energy in transfer to or from a thermodynamic system by mechanisms other than t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Waves
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons. Electromagnetic radiation is produced by accelerating charged particles such as from the Sun and other celestial bodies or artificially generated for various applications. Its interaction with matter depends on wavelength, influencing its uses in communication, medicine, industry, and scientific research. Radio waves enable broadcasting and Wireless, wireless communication, infrared is used in Thermography, thermal imaging, visible light is essential for vision, and higher-energy radiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Electrodynamics
In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomenon, phenomena involving electric charge, electrically charged particles interacting by means of exchange of photons and represents the quantum mechanics, quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction. In technical terms, QED can be described as a perturbation theory (quantum mechanics), perturbation theory of the electromagnetic Quantum vacuum state, quantum vacuum. Richard Feynman called it "the jewel of physics" for its precision tests of QED, extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stefan–Boltzmann Law
The Stefan–Boltzmann law, also known as ''Stefan's law'', describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Ludwig Boltzmann who derived the law theoretically. For an ideal absorber/emitter or black body, the Stefan–Boltzmann law states that the total energy radiated per unit area, surface area per unit time (also known as the ''radiant exitance'') is directly Proportionality (mathematics), proportional to the fourth power of the black body's temperature, : M^ = \sigma\, T^. The constant of proportionality, \sigma, is called the Stefan–Boltzmann constant. It has the value In the general case, the Stefan–Boltzmann law for radiant exitance takes the form: M = \varepsilon\, M^ = \varepsilon\,\sigma\, T^4 , where \varepsilon is the emissivity of the surface emitting the radiation. The emissivity is generally between zero and one. An emiss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
