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The standard example of a longitudinal wave is a sound wave or "pressure wave" in gases, liquids, or solids, whose oscillations cause compression and expansion of the material through which the wave is propagating. Pressure waves are called "primary waves", or "P-waves" in geophysics. Water waves involve both longitudinal and transverse motions ...
The expression for the infinitesimal reversible change in the Gibbs free energy as a function of its "natural variables" p and T, for an open system, subjected to the operation of external forces (for instance, electrical or magnetic) X i, which cause the external parameters of the system a i to change by an amount da i, can be derived as ...
The technique enhances the perception of sound spatialization by exploiting sound localization: a listener's ability to identify the location or origin of a detected sound in direction and distance. This is achieved by using multiple discrete audio channels routed to an array of loudspeakers . [ 1 ]
A monochromatic wave (a wave of a single frequency) consists of successive troughs and crests, and the distance between two adjacent crests or troughs is called the wavelength. Waves of the electromagnetic spectrum vary in size, from very long radio waves longer than a continent to very short gamma rays smaller than atom nuclei.
Sound is a traveling longitudinal wave, which is an oscillation of pressure. Humans perceive the frequency of a sound as its pitch. Each musical note corresponds to a particular frequency. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20 000 Hz; the average adult human can hear sounds between 20 Hz and 16 000 Hz. [11]
1.5 kW is the maximum legal power output of a US ham radio station. [12] 60 dBm: 1 kW = 1,000 W: Typical combined radiated RF power of microwave oven elements 55 dBm ~300 W: Typical single-channel RF output power of a K u band geostationary satellite: 50 dBm: 100 W: Typical total thermal radiation emitted by a human body, peak at 31.5 THz (9.5 μm)
In high power VLF transmitters, to increase the allowable data rate, a special form of FSK called minimum-shift keying (MSK) is used. This is required due to the high Q of the antenna. [ 8 ] : 3.2–3.4, §3.1.1 The huge capacitively-loaded antenna and loading coil form a high Q tuned circuit , which stores oscillating electrical energy.
The Mosquito or Mosquito alarm is a machine used to deter loitering by emitting sound at high frequency. In some versions, it is intentionally tuned to be heard primarily by younger people. Nicknamed "Mosquito" for the buzzing sound it plays, the device is marketed as a safety and security tool for preventing youths from congregating in ...