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  2. Extremely low frequency - Wikipedia

    en.wikipedia.org/wiki/Extremely_low_frequency

    The rights of way of the two perpendicular 14 mile (23 km) overhead transmission lines that constituted the ground dipole antenna which radiated the ELF waves can be seen at lower left. Extremely low frequency (ELF) is the ITU designation [1] for electromagnetic radiation (radio waves) with frequencies from 3 to 30 Hz, and corresponding ...

  3. Electromagnetic radiation and health - Wikipedia

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

    Extremely low frequency EM waves can span from 0 Hz to 3 kHz, though definitions vary across disciplines. The maximum recommended exposure for the general public is 5 kV/m. [20] ELF waves around 50 Hz to 60 Hz are emitted by power generators, transmission lines and distribution lines, power cables, and electric appliances. Typical household ...

  4. Non-ionizing radiation - Wikipedia

    en.wikipedia.org/wiki/Non-ionizing_radiation

    Extremely low frequency (ELF) is the range of radiation frequencies from 300 Hz to 3 kHz. In atmosphere science, an alternative definition is usually given, from 3 Hz to 3 kHz. [ 7 ] In the related magnetosphere science, the lower frequency electromagnetic oscillations (pulsations occurring below ~3 Hz) are considered to be in the ULF range ...

  5. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and ...

  6. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    Each has an energy related to the frequency of the wave given by Planck's relation E = hf, where E is the energy of the photon, h is the Planck constant, 6.626 × 10 −34 J·s, and f is the frequency of the wave. [40] In a medium (other than vacuum), velocity factor or refractive index are considered, depending on frequency and application ...

  7. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    Military very low frequency (VLF) and extremely low frequency (ELF) communication systems can communicate over most of the Earth. VLF and ELF radio waves can also penetrate water to hundreds of meters deep, so they are used to communicate with submerged submarines .

  8. Radiation - Wikipedia

    en.wikipedia.org/wiki/Radiation

    Extremely low frequency (ELF) is radiation frequencies from 3 to 30 Hz (10 8 to 10 7 m respectively). In atmosphere science, an alternative definition is usually given, from 3 Hz to 3 kHz. [ 4 ]

  9. Earth–ionosphere waveguide - Wikipedia

    en.wikipedia.org/wiki/Earth–ionosphere_waveguide

    Extremely low frequency (ELF) (< 3 kHz) and very low frequency (VLF) (3–30 kHz) signals can propagate efficiently in this waveguide. For instance, lightning strikes launch a signal called radio atmospherics , which can travel many thousands of kilometers, because they are confined between the Earth and the ionosphere.