|
Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.[1][2] It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns.[3][4] The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter lambda (λ) [...More Info...] [...Related Items...] |
Free Space
A vacuum is space devoid of matter. The word stems from the Latin adjective vacuus for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure.[1] Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure.[2] The Latin term in vacuo is used to describe an object that is surrounded by a vacuum. The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum [...More Info...] [...Related Items...] |
Vibration Spectrum
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 1013 Hz to approximately 1014 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm−1. In general, a non-linear molecule with N atoms has 3N – 6 normal modes of vibration, but a linear molecule has 3N – 5 modes, because rotation about the molecular axis cannot be observed.[1] A diatomic molecule has one normal mode of vibration, since it can only stretch or compress the single bond [...More Info...] [...Related Items...] |
Electric Field
An electric field (sometimes E-field[1]) is the physical field that surrounds each electric charge and exerts force on all other charges in the field, either attracting or repelling them.[2][3] Electric fields originate from electric charges, or from time-varying magnetic fields. Electric fields and magnetic fields are both manifestations of the electromagnetic force, one of the four fundamental forces (or interactions) of nature. Electric fields are important in many areas of physics, and are exploited practically in electrical technology. In atomic physics and chemistry, for instance, the electric field is used to model the attractive force holding the atomic nucleus and electrons together in atoms [...More Info...] [...Related Items...] |
