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  2. Human thermoregulation - Wikipedia

    en.wikipedia.org/wiki/Human_thermoregulation

    There are four avenues of heat loss: convection, conduction, radiation, and evaporation. If skin temperature is greater than that of the surroundings, the body can lose heat by radiation and conduction. But, if the temperature of the surroundings is greater than that of the skin, the body actually gains heat by radiation and conduction. In such ...

  3. Stimulated emission - Wikipedia

    en.wikipedia.org/wiki/Stimulated_emission

    Stimulated emission was a theoretical discovery by Albert Einstein within the framework of the old quantum theory, wherein the emission is described in terms of photons that are the quanta of the EM field. [5] [6] Stimulated emission can also occur in classical models, without reference to photons or quantum-mechanics.

  4. Thermoregulation - Wikipedia

    en.wikipedia.org/wiki/Thermoregulation

    There are four avenues of heat loss: evaporation, convection, conduction, and radiation. If skin temperature is greater than that of the surrounding air temperature, the body can lose heat by convection and conduction. However, if air temperature of the surroundings is greater than that of the skin, the body gains heat by convection and ...

  5. Thermoception - Wikipedia

    en.wikipedia.org/wiki/Thermoception

    In physiology, thermoception or thermoreception is the sensation and perception of temperature, or more accurately, temperature differences inferred from heat flux.It deals with a series of events and processes required for an organism to receive a temperature stimulus, convert it to a molecular signal, and recognize and characterize the signal in order to trigger an appropriate defense response.

  6. Population inversion - Wikipedia

    en.wikipedia.org/wiki/Population_inversion

    The rate at which stimulated emission occurs is proportional to the number of atoms N 2 in the excited state, and the radiation density of the light. The base probability of a photon causing stimulated emission in a single excited atom was shown by Albert Einstein to be exactly equal to the probability of a photon being absorbed by an atom in ...

  7. Thermal radiation - Wikipedia

    en.wikipedia.org/wiki/Thermal_radiation

    A black body is also a perfect emitter. The radiation of such perfect emitters is called black-body radiation. The ratio of any body's emission relative to that of a black body is the body's emissivity, so a black body has an emissivity of one. Absorptivity, reflectivity, and emissivity of all bodies are dependent on the wavelength of the ...

  8. Cold and heat adaptations in humans - Wikipedia

    en.wikipedia.org/wiki/Cold_and_heat_adaptations...

    There are two types of heat the body is adapted to, humid heat and dry heat, but the body adapts to both in similar ways. Humid heat is characterized by warmer temperatures with a high amount of water vapor in the air, while dry heat is characterized by warmer temperatures with little to no vapor, such as desert conditions.

  9. Einstein coefficients - Wikipedia

    en.wikipedia.org/wiki/Einstein_coefficients

    Schematic diagram of atomic stimulated emission. Stimulated emission (also known as induced emission) is the process by which an electron is induced to jump from a higher energy level to a lower one by the presence of electromagnetic radiation at (or near) the frequency of the transition. From the thermodynamic viewpoint, this process must be ...