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  2. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    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 gamma rays. The electromagnetic waves in each of these bands have different characteristics, such as how they are ...

  3. Frequency - Wikipedia

    en.wikipedia.org/wiki/Frequency

    At even lower frequency, the wave is called a microwave, and at still lower frequencies it is called a radio wave. Likewise, an electromagnetic wave with a frequency higher than 8 × 10 14 Hz will also be invisible to the human eye; such waves are called ultraviolet (UV) radiation.

  4. Wavenumber - Wikipedia

    en.wikipedia.org/wiki/Wavenumber

    In the physical sciences, the wavenumber (or wave number), also known as repetency, [1] is the spatial frequency of a wave. Ordinary wavenumber is defined as the number of wave cycles divided by length; it is a physical quantity with dimension of reciprocal length , expressed in SI units of cycles per metre or reciprocal metre (m −1 ).

  5. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    In 1887, German physicist Heinrich Hertz demonstrated the reality of Maxwell's electromagnetic waves by experimentally generating electromagnetic waves lower in frequency than light, radio waves, in his laboratory, [6] showing that they exhibited the same wave properties as light: standing waves, refraction, diffraction, and polarization.

  6. Hertz - Wikipedia

    en.wikipedia.org/wiki/Hertz

    The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. [1] [a] The hertz is an SI derived unit whose formal expression in terms of SI base units is s −1, meaning that one hertz is one per second or the reciprocal of one second. [2]

  7. 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 ...

  8. Radio propagation - Wikipedia

    en.wikipedia.org/wiki/Radio_propagation

    Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]

  9. Orders of magnitude (frequency) - Wikipedia

    en.wikipedia.org/.../Orders_of_magnitude_(frequency)

    Acoustic – frequency of G −7, the lowest note sung by the singer with the deepest voice in the world, Tim Storms. His vocal cords vibrate 1 time every 5.29 seconds. 10 0: 1 hertz (Hz) 1 to 1.66 Hz: Approximate frequency of an adult human's resting heart beat: 1 Hz: 60 bpm, common tempo in music 2 Hz: 120 bpm, common tempo in music ~7.83 Hz