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  2. Radiation pressure - Wikipedia

    en.wikipedia.org/wiki/Radiation_pressure

    Direct applications of the radiation pressure force in these fields are, for example, laser cooling (the subject of the 1997 Nobel Prize in Physics), [5] quantum control of macroscopic objects and atoms (2012 Nobel Prize in Physics), [6] interferometry (2017 Nobel Prize in Physics) [7] and optical tweezers (2018 Nobel Prize in Physics). [8 ...

  3. Stefan–Boltzmann law - Wikipedia

    en.wikipedia.org/wiki/Stefan–Boltzmann_law

    [3]: 66n, 541 (This is a trivial conclusion, since the emissivity, , is defined to be the quantity that makes this equation valid. What is non-trivial is the proposition that ε ≤ 1 {\displaystyle \varepsilon \leq 1} , which is a consequence of Kirchhoff's law of thermal radiation .

  4. Poynting vector - Wikipedia

    en.wikipedia.org/wiki/Poynting_vector

    In physics, the Poynting vector (or Umov–Poynting vector) represents the directional energy flux (the energy transfer per unit area, per unit time) or power flow of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m 2 ); kg/s 3 in base SI units.

  5. Boltzmann equation - Wikipedia

    en.wikipedia.org/wiki/Boltzmann_equation

    The equation is a nonlinear integro-differential equation, and the unknown function in the equation is a probability density function in six-dimensional space of a particle position and momentum. The problem of existence and uniqueness of solutions is still not fully resolved, but some recent results are quite promising.

  6. List of physical quantities - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_quantities

    Pressure gradient: Pressure per unit distance pascal/m L −2 M 1 T −2: vector Temperature gradient: steepest rate of temperature change at a particular location K/m L −1 Θ: vector Torque: τ: Product of a force and the perpendicular distance of the force from the point about which it is exerted

  7. Photon gas - Wikipedia

    en.wikipedia.org/wiki/Photon_gas

    In physics, a photon gas is a gas-like collection of photons, which has many of the same properties of a conventional gas like hydrogen or neon – including pressure, temperature, and entropy. The most common example of a photon gas in equilibrium is the black-body radiation .

  8. Radiative transfer - Wikipedia

    en.wikipedia.org/wiki/Radiative_transfer

    Radiative transfer (also called radiation transport) is the physical phenomenon of energy transfer in the form of electromagnetic radiation. The propagation of radiation through a medium is affected by absorption, emission, and scattering processes. The equation of radiative transfer describes these interactions mathematically. Equations of ...

  9. Einstein field equations - Wikipedia

    en.wikipedia.org/wiki/Einstein_field_equations

    The Einstein field equations (EFE) may be written in the form: [5] [1] + = EFE on the wall of the Rijksmuseum Boerhaave in Leiden, Netherlands. where is the Einstein tensor, is the metric tensor, is the stress–energy tensor, is the cosmological constant and is the Einstein gravitational constant.