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  2. Speed of sound - Wikipedia

    en.wikipedia.org/wiki/Speed_of_sound

    The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air, is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.

  3. 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]

  4. Line-of-sight propagation - Wikipedia

    en.wikipedia.org/wiki/Line-of-sight_propagation

    Line of sight (LoS) propagation from an antenna. Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves can only travel in a direct visual path from the source to the receiver without obstacles. [1] Electromagnetic transmission includes light emissions traveling in a straight line.

  5. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    Equivalently, , the distance that a radio wave travels in vacuum in one second, is 299,792,458 meters (983,571,056 ft), which is the wavelength of a 1 hertz radio signal. A 1 megahertz radio wave (mid-AM band) has a wavelength of 299.79 meters (983.6 ft).

  6. Sound - Wikipedia

    en.wikipedia.org/wiki/Sound

    When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed or focused). [5] Spherical compression (longitudinal) waves. The mechanical vibrations that can be interpreted as sound can travel through all forms of matter: gases, liquids, solids, and plasmas.

  7. Isotropic radiator - Wikipedia

    en.wikipedia.org/wiki/Isotropic_radiator

    The waves travel in straight lines away from the source point, in the radial direction ^. Since it has no preferred direction of radiation, the power density S {\displaystyle \left\langle S\right\rangle } [ 7 ] of the waves at any point does not depend on the angular direction ( θ , ϕ ) {\displaystyle (\theta ,\phi )} , but only on the ...

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    mail.aol.com

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  9. Fresnel zone - Wikipedia

    en.wikipedia.org/wiki/Fresnel_zone

    The primary wave will travel in a relative straight line from the transmitter to the receiver. Aberrant transmitted radio, sound, or light waves which are transmitted at the same time can follow slightly different paths before reaching a receiver, especially if there are obstructions or deflecting objects between the two. The two waves can ...