Examples of black body radiation in the following topics:
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- A black body emits radiation called black body radiation.
- A black body in thermal equilibrium (i.e. at a constant temperature) emits electromagnetic radiation called black body radiation.
- Black body radiation has a characteristic, continuous frequency spectrum that depends only on the body's temperature.
- The puzzle was solved in 1901 by Max Planck in the formalism now known as Planck's law of black-body radiation.
- Identify assumption made by Max Planck to describe the electromagnetic radiation emitted by a black body
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- Mid-infrared, from 30 to 120 THz (10 to 2.5 μm) - Hot objects (black-body radiators) can radiate strongly in this range, and human skin at normal body temperature radiates strongly at the lower end of this region.
- Infrared radiation is popularly known as "heat radiation," but light and electromagnetic waves of any frequency will heat surfaces that absorb them.
- Objects at room temperature will emit radiation mostly concentrated in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see sections on black body radiation and Wien's displacement law).
- This is a property of a surface which describes how its thermal emissions deviate from the ideal of a black body.
- Many astronomical objects emit detectable amounts of IR radiation at non-thermal wavelengths.
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- The electrons can only orbit stably, without radiating, in certain orbits (called by Bohr the "stationary orbits") at a certain discrete set of distances from the nucleus.
- In these orbits, the electron's acceleration does not result in radiation and energy loss as required by classical electrodynamics.
- Electrons can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency $\nu$ determined by the energy difference of the levels according to the Planck relation: $\Delta{E} = E_2-E_1=h\nu$ , where $h$ is the Planck constant.
- We have seen that Planck adopted a new condition of energy quantization to explain the black body radiation, where he introduced the Planck constant $h$ for the first time.
- Soon after, Einstein resorted to this new concept of energy quantization and used the Planck constant again to explain the photoelectric effects, in which he assumed that electromagnetic radiation interact with matter as particles (later named "photons").
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- Electrons are emitted from matter that is absorbing energy from electromagnetic radiation, resulting in the photoelectric effect.
- The energy of the individual photoelectrons increased with the frequency (or color) of the light, but was independent of the intensity (or brightness) of the radiation.
- Building on Max Planck's theory of black body radiation, Einstein theorized that the energy in each quantum of light was equal to the frequency multiplied by a constant $h$, later called Planck's constant.
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- Electromagnetic radiation can essentially be described as photon streams.
- Planck theorized that "black bodies" (thermal radiators) and other forms of electromagnetic radiation existed not as spectra, but in discrete, "quantized" form.
- Momentum is classically defined as the product of mass and velocity and thus would intuitively seem irrelevant to a discussion of electromagnetic radiation, which is both massless and composed of waves.
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- The hot body emits electromagnetic waves that are absorbed by our skin, and no medium is required for them to propagate.
- The reverse is also true—black radiates better than gray.
- Thus, on a clear summer night the asphalt will be colder than the gray sidewalk because black radiates energy more rapidly than gray.
- An ideal jet-black (or blackbody) radiator has e=1, whereas a perfect reflector has e=0.
- A black object is a good absorber and a good radiator, while a white (or silver) object is a poor absorber and a poor radiator.
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- Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency and therefore high energy.
- Gamma rays are ionizing radiation and are thus biologically hazardous.
- Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900, while studying radiation emitted from radium during its gamma decay.
- Gamma rays and neutrons are more penetrating, causing diffuse damage throughout the body (e.g., radiation sickness, cell's DNA damage, cell death due to damaged DNA, increasing incidence of cancer) rather than burns.
- Bright spots within the galactic plane are pulsars (spinning neutron stars with strong magnetic fields), while those above and below the plane are thought to be quasars (galaxies with supermassive black holes actively accreting matter).
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- Radiation therapy uses ionizing radiation to treat conditions such as hyperthyroidism, cancer, and blood disorders.
- Radiation therapy is particularly effective as a treatment of a number of types of cancer if they are localized to one area of the body.
- Brachytherapy is another form of radiation therapy, in which a therapeutic radioisotope is injected into the body to chemically localize to the tissue that requires destruction .
- Radiation therapy of the pelvis.
- Body sites in which brachytherapy can be used to treat cancer
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- Radiation therapy uses ionizing radiation to treat conditions such as hyperthyroidism, cancer, and blood disorders.
- The nuclear medicine whole body bone scan is generally used in evaluations of various bone related pathology, such as for bone pain, stress fracture, nonmalignant bone lesions, bone infections, or the spread of cancer to the bone.
- Radiation therapy is particularly effective as a treatment of a number of types of cancer if they are localized to one area of the body.
- Brachytherapy is another form of radiation therapy, in which a therapeutic radioisotope is injected into the body to chemically localize to the tissue that requires destruction .
- Radiation therapy of the pelvis.
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- Ionizing radiation is generally harmful, even potentially lethal, to living organisms.
- Although radiation was discovered in the late 19th century, the dangers of radioactivity and of radiation were not immediately recognized.
- Other conditions, such as radiation burns, acute radiation syndrome, chronic radiation syndrome, and radiation-induced thyroiditis are deterministic, meaning they reliably occur above a threshold dose and their severity increases with dose.
- Two pathways of exposure to ionizing radiation exist.
- When radioactive compounds enter the human body, the effects are different from those resulting from exposure to an external radiation source.