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Scientific pitch, also known as philosophical pitch, Sauveur pitch or Verdi tuning, is an absolute concert pitch standard which is based on middle C (C 4) being set to 256 Hz rather than ~ 261.63 Hz, [a] making it ~ 31.77 cents lower than the common A440 pitch standard.
Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals , radio waves, and light. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), the period—the time interval between beats—is half a second (60 ...
All quantities are in Gaussian units except energy and temperature which are in electronvolts.For the sake of simplicity, a single ionic species is assumed. The ion mass is expressed in units of the proton mass, = / and the ion charge in units of the elementary charge, = / (in the case of a fully ionized atom, equals to the respective atomic number).
Metals are only transparent to light with a frequency higher than the metal's plasma frequency. For typical metals such as aluminium or silver, is approximately 10 23 cm −3, which brings the plasma frequency into the ultraviolet region. This is why most metals reflect visible light and appear shiny.
[4] [5] In addition, in non-centrosymmetric crystals belonging to crystallographic point group 432, SHG is not possible [6] and under Kleinman's conditions SHG in 422 and 622 point groups should vanish, [7] although some exceptions exist. [8] In some cases, almost 100% of the light energy can be converted to the second-harmonic frequency.
A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.
An ionized plasma may be efficiently produced or heated by superimposing a static magnetic field and a high-frequency electromagnetic field at the electron cyclotron resonance frequency. In the toroidal magnetic fields used in magnetic fusion energy research, the magnetic field decreases with the major radius, so the location of the power ...
[1] [2] Soon the term referred to a plot of light intensity or power as a function of frequency or wavelength, also known as a spectral density plot. Later it expanded to apply to other waves, such as sound waves and sea waves that could also be measured as a function of frequency (e.g., noise spectrum, sea wave spectrum).