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  2. Schumann resonances - Wikipedia

    en.wikipedia.org/wiki/Schumann_resonances

    The global electromagnetic resonance phenomenon is named after physicist Winfried Otto Schumann who predicted it mathematically in 1952. Schumann resonances are the principal background in the part of the electromagnetic spectrum [2] from 3 Hz through 60 Hz [3] and appear as distinct peaks at extremely low frequencies around 7.83 Hz (fundamental), 14.3, 20.8, 27.3, and 33.8 Hz.

  3. Extremely low frequency - Wikipedia

    en.wikipedia.org/wiki/Extremely_low_frequency

    The fundamental Schumann resonance is at approximately 7.83 Hz, the frequency at which the wavelength equals the circumference of the Earth, and higher harmonics occur at 14.1, 20.3, 26.4, and 32.4 Hz, etc. Lightning strikes excite these resonances, causing the Earth–ionosphere cavity to "ring" like a bell, resulting in a peak in the noise ...

  4. List of effects - Wikipedia

    en.wikipedia.org/wiki/List_of_effects

    Nuclear Overhauser effect (chemical physics) (nuclear magnetic resonance) (physical chemistry) (spectroscopy) Numerosity adaptation effect (cognitive science) (optical illusions) (perception) Nut Island effect (human resource management) (organizational studies and human resource management)

  5. Electromagnetic radiation and health - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation...

    Since 1962, the microwave auditory effect or tinnitus has been shown from radio frequency exposure at levels below significant heating. [34] Studies during the 1960s in Europe and Russia claimed to show effects on humans, especially the nervous system, from low energy RF radiation; the studies were disputed at the time. [35] [36]

  6. Lists of foods - Wikipedia

    en.wikipedia.org/wiki/Lists_of_foods

    Of more than 50,000 edible plant species in the world, only a few hundred contribute significantly to human food supplies. Just 15 crop plants provide 90 percent of the world's food energy intake (exclusive of meat), with rice, maize and wheat comprising two-thirds of human food consumption. These three alone are the staples of over 4 billion ...

  7. Earth–ionosphere waveguide - Wikipedia

    en.wikipedia.org/wiki/Earth–ionosphere_waveguide

    The dispersion characteristics of the Earth-ionospheric waveguide can be used for locating thunderstorm activity by measurements of the difference of the group time delay of lightning signals at adjacent frequencies up to distances of 10000 km. [7] The Schumann resonances allow to determine the global lightning activity.

  8. Winfried Otto Schumann - Wikipedia

    en.wikipedia.org/wiki/Winfried_Otto_Schumann

    Winfried Otto Schumann (May 20, 1888 – September 22, 1974) was a German physicist and electrical engineer who predicted the Schumann resonances, a series of low-frequency resonances caused by lightning discharges in the atmosphere.

  9. Resonator - Wikipedia

    en.wikipedia.org/wiki/Resonator

    To cause resonance, the phase of a sinusoidal wave after a round trip must be equal to the initial phase so the waves self-reinforce. The condition for resonance in a resonator is that the round trip distance, 2 d {\displaystyle 2d\,} , is equal to an integer number of wavelengths λ {\displaystyle \lambda \,} of the wave: