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  2. 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 ...

  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. Infrasound - Wikipedia

    en.wikipedia.org/wiki/Infrasound

    20 Hz is considered the normal low-frequency limit of human hearing. When pure sine waves are reproduced under ideal conditions and at very high volume, a human listener will be able to identify tones as low as 12 Hz. [38] Below 10 Hz it is possible to perceive the single cycles of the sound, along with a sensation of pressure at the eardrums.

  5. Health effects from noise - Wikipedia

    en.wikipedia.org/wiki/Health_effects_from_noise

    Noise-induced hearing loss is a permanent shift in pure-tone thresholds, resulting in sensorineural hearing loss. The severity of a threshold shift is dependent on duration and severity of noise exposure. Noise-induced threshold shifts are seen as a notch on an audiogram from 3000 to 6000 Hz, but most often at 4000 Hz. [16]

  6. Extremely high frequency - Wikipedia

    en.wikipedia.org/wiki/Extremely_high_frequency

    [6] [7] [8] Absorption by atmospheric gases is a significant factor throughout the band and increases with frequency. However, this absorption is maximum at a few specific absorption lines, mainly those of oxygen at 60 GHz and water vapor at 24 GHz and 184 GHz. [7]

  7. Why Is 7-Eleven Open 24 Hours If It’s Called “7 ... - AOL

    www.aol.com/why-7-eleven-open-24-155201567.html

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  8. Terahertz radiation - Wikipedia

    en.wikipedia.org/wiki/Terahertz_radiation

    Terahertz waves lie mostly at the far end of the infrared band, the longest ones in the microwave band. Terahertz radiation – also known as submillimeter radiation, terahertz waves, tremendously high frequency [1] (THF), T-rays, T-waves, T-light, T-lux or THz – consists of electromagnetic waves within the International Telecommunication Union-designated band of frequencies from 0.1 to 10 ...

  9. Yosemite’s Half Dome cables are dangerous. Here’s why they ...

    www.aol.com/yosemite-half-dome-cables-dangerous...

    But there’s no real reason, besides bureaucratic stubbornness, why the Half Dome cables need to be so dangerous. It’s a wonder more people haven’t died. It’s a wonder more people haven’t ...