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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 hertz is defined as one per second for periodic events. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" [3] [4] and then adds: "It follows that the hyperfine splitting in the ground state of the ...
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.
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)
millimeter wave radar research, molecular rotational spectroscopy and other kinds of scientific research W band: 75 to 110 GHz: 2.7 mm to 4.0 mm satellite communications, millimeter-wave radar research, military radar targeting and tracking applications, and some non-military applications, automotive radar F band: 90 to 140 GHz: 2.1 mm to 3.3 mm
Renewable energy sources are even larger than the traditional fossil fuels and in theory can easily supply the world's energy needs. 89 PW [32] of solar power falls on the planet's surface. While it is not possible to capture all, or even most, of this energy, capturing less than 0.02% would be enough to meet the current energy needs.
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.
Microturbines have around 15% efficiencies without a recuperator, 20 to 30% with one and they can reach 85% combined thermal-electrical efficiency in cogeneration. [2] The recuperated Niigata Power Systems 300 kW (400 hp) RGT3R thermal efficiency reaches 32.5% while the 360 kW (480 hp) non recuperated RGT3C is at 16.3%. [7]