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  2. Utility frequency - Wikipedia

    en.wikipedia.org/wiki/Utility_frequency

    The waveform of 230 V and 50 Hz compared with 120 V and 60 Hz. The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user.

  3. The Hum - Wikipedia

    en.wikipedia.org/wiki/The_Hum

    While the Hum is hypothesized by some to be a form of low frequency tinnitus [7] such as the venous hum, some report it not to be internal, being worse inside their homes than outside; however, others insist that it is equally bad indoors and outdoors. Some people notice the Hum only at home, while others hear it everywhere they go.

  4. 60 Hz - Wikipedia

    en.wikipedia.org/wiki/60_Hz

    Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Pages for logged out editors learn more

  5. Mains hum - Wikipedia

    en.wikipedia.org/wiki/Mains_hum

    Mains hum, electric hum, cycle hum, or power line hum is a sound associated with alternating current which is twice the frequency of the mains electricity.The fundamental frequency of this sound is usually double that of fundamental 50/60 Hz, i.e., 100/120 Hz, depending on the local power-line frequency.

  6. Fluorescent lamps and health - Wikipedia

    en.wikipedia.org/wiki/Fluorescent_lamps_and_health

    An open (single envelope) CFL [12] An encapsulated/closed (double envelope) CFL. Some fluorescent lamps emit ultraviolet radiation. [citation needed] The Health Protection Agency of the United Kingdom has conducted research concluding that exposure to open (single envelope) compact fluorescent lamps (CFLs) for over 1 hour per day at a distance of less than 30 cm can exceed guideline levels as ...

  7. Mains electricity - Wikipedia

    en.wikipedia.org/wiki/Mains_electricity

    Mains electricity or utility power, grid power, domestic power, and wall power, or, in some parts of Canada, hydro, is a general-purpose alternating-current (AC) electric power supply.

  8. Static electricity - Wikipedia

    en.wikipedia.org/wiki/Static_electricity

    Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it can move away by an electric current or electrical discharge.

  9. Hearing range - Wikipedia

    en.wikipedia.org/wiki/Hearing_range

    A basic measure of hearing is afforded by an audiogram, a graph of the absolute threshold of hearing (minimum discernible sound level) at various frequencies throughout an organism's nominal hearing range.