- 3137 - PLANCK CONSTANT - the smallest constant in physics. The Planck constant is related to the quantization of light and matter. It can be seen as a subatomic-scale constant. In a unit system adapted to subatomic scales, the electronvolt is the appropriate unit of energy and the petahertz the appropriate unit of frequency. Atomic unit systems are based on the Planck constant.
------------------ 3137 - PLANCK CONSTANT - the smallest constant?
- Planck's constant relates the energy of a photon with the frequency of light. It is the quantum of electromagnetic action that relates a photon’s energy to its frequency. The Planck constant multiplied by a photon’s frequency is equal to a photon’s energy. The Planck constant is a fundamental physical constant denoted as “h” , and of fundamental importance in quantum mechanics.
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- The Planck constant is one of the smallest constants used in physics. This reflects the fact that on a scale adapted to humans, where energies are typical of the order of kilojoules and times are typical of the order of seconds or minutes, the Planck constant (the quantum of action) is very small. One can regard the Planck constant to be only relevant to the microscopic scale instead of the macroscopic scale in our everyday experience.
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- The Planck constant is defined to have the exact value = 6.62607015×10−34 Joule-seconds in SI units.
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- Planck's constant allows the precise calculation of the energy of light emitted or absorbed and thereby permits the determination of the actual energy of the photon. Along with constant for the speed of light, Planck's constant is a fundamental constant of nature.
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- At the beginning of the twentieth century, German physicist, Maxwell Planck, proposed that atoms absorb or emit electromagnetic radiation only in certain units or bundles of energy termed “quanta“.
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- The concept that energy existed only in discrete and defined units seemed counter-intuitive, outside the human experience with nature. Accepting his experimental results regarding the radiation emitted by an object as its temperature increases, Planck developed a quantum theory that accounts for a wide range of physical phenomena.
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- Prior to Planck's work, electromagnetic radiation (light) was thought travel in waves with an infinite number of available frequencies and wavelengths. Planck determined that energy of light was proportional to its frequency. As the frequency of light increases, so does the energy of the light.
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- Planck began his university studies at the age of sixteen. By the age of twenty-one he had earned a doctorate in physics. While a graduate student, Planck studied entropy and the applications of the second law of thermo-dynamics.
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- When Planck started his studies in physics, Newtonian or classical physics seemed fully explained. In fact, Planck's advisor claimed that there was essentially nothing new to discover in physics. Despite such warnings, Planck choose to study physics.
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- Planck's talents and dedication were recognized and upon the death of his mentor Gustav Robert Kirchoff, Planck became a professor of theoretical physics at the University of Berlin were he did the major portion of his work regarding the relationship of light energy to light wavelength.
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- Planck was able to measure radiation from heated bodies because although atoms are constantly vibrating and generating electromagnetic waves when heated, an atom vibrates at higher frequencies and gives off radiation at higher levels of energy.
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- Planck admitted that he did not fully understand quantum theory. In fact he regarded it as only a mathematical aberration or temporary answer until a more intuitive or common sense answer was found.
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- Despite Planck's reservations, Albert Einstein's subsequent Nobel Prize winning work on the photoelectric effect was heavily based on Planck's theory and described light as being composed of photons, each with an energy equal to Planck's constant times the frequency of the light.
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- Light is now understood as having both photon (particle) and wave-like properties.
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- In 1916, American physicist Robert Millikan's experiments gave the first precise calculation of Planck's constant. Modern laboratories, including the National Institute of Standards and Technology strive for more precise values for Planck's constant because it is so fundamental to applications of modern physics and chemistry.
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- Planck's constant, combined with the speed of light, and the universal gravitational constant (G), can yield a quantity with the dimensions of time (5.38 x 10-44 seconds).
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- This quantity is called “Planck time” a very important concept in cosmology. Because it is a fundamental constant, more precise values for Planck's constant also improves the precision of related atomic constants, such as proton mass, electron mass, elementary charge, and Avogadro's number.
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- At the end of the 19th century, accurate measurements of the spectrum of black body radiation existed, but predictions of the frequency distribution of the radiation by then-existing theories diverged significantly at higher frequencies. In 1900, Max Planck empirically derived a formula for the observed spectrum.
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- He assumed 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. He was able to calculate the proportionality constant, , from the experimental measurements, and that constant is named in his honor.
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- The black-body problem was revisited in 1905, Einstein independently proved that classical electromagnetism could never account for the observed spectrum. These proofs are commonly known as the “ultraviolet catastrophe”.
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- They contributed greatly, along with Einstein’s work on the photoelectric effect, in convincing physicists that Planck’s postulate of quantized energy levels was more than a mere mathematical formalism. The first Solvay Conference in 1911 was devoted to “the theory of radiation and quanta”.
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- Einstein’s explanation for observations of photoelectric effect was that light itself is quantized; that the energy of light is not transferred continuously as in a classical wave, but only in small “packets” or quanta. The size of these “packets” of energy, which would later be named photons, was to be the same as Planck’s “energy element”, giving the modern version of the Planck–Einstein relation:
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- The Planck constant also occurs in statements of Werner Heisenberg’s uncertainty principle.
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--------------------------------- Other reviews available;
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- 2396 - PLANCK - the smallest things- The answer to the enduring question of the smallest thing in the universe has evolved along with humanity. People once thought grains of sand were the building blocks of what we see around us. Then the atom was discovered, and it was thought indivisible.
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- 2397 - PLANCK TIME - Time Come to Us in Particles. Time seems continuous. But, there are actually quantum steps in time. The second hand on your watch seems to jump in steps. Time itself does the same thing in much, much smaller steps.
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- 2641 - What Forces Control Everything? A force is a push or a pull. So, a force is something that moves something. Not really, no force is needed if something is moving at a constant velocity in a straight line. But, a force is needed to accelerate something, to “change” its velocity, or, to change it from moving in a straight line. Energy is a force acting over a distance. (E = F*d) So, to move something through space takes energy. The force of gravity has potential energy that can quickly change into kinetic energy if you step off a cliff. The electric force is between electric charges. The magnetic force is between magnetic poles. But, combine these two and you get electromagnetic radiation which is light.
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- April 25, 2021 PLANCK CONSTANT - the smallest constant 3137
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