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The transmission of an etalon as a function of wavelength. A high-finesse etalon (red line) shows sharper peaks and lower transmission minima than a low-finesse etalon (blue). The free spectral range is Δλ (shown above the graph). The FSR is related to the full-width half-maximum δλ of any one transmission band by a quantity known as the ...
Mean free path. In physics, mean free path is the average distance over which a moving particle (such as an atom, a molecule, or a photon) travels before substantially changing its direction or energy (or, in a specific context, other properties), typically as a result of one or more successive collisions with other particles.
The unit of substance in the FPS system is the pound-mole (lb-mol) = 273.16 × 1024. Until the SI decided to adopt the gram-mole, the mole was directly derived from the mass unit as (mass unit)/ (atomic mass unit). The unit (lbf⋅s 2 /ft)-mol also appears in a former definition of the atmosphere.
A centimetre (International spelling) or centimeter ( American spelling ), with SI symbol cm, is a unit of length in the International System of Units (SI) equal to one hundredth of a metre, centi being the SI prefix for a factor of 1 100. [1] Equivalently, there are 100 centimetres in 1 metre. The centimetre was the base unit of length in the ...
From these figures for the size of a Biblical ell, that of the basic unit — the finger-breadth ( Etzba) — can be calculated to be either 2.1 or 2.2 cm (0.83 or 0.87 in); Rav Avraham Chaim Naeh approximates at 2 cm (0.79 in); Talmudic scholar Chazon Ish at 2.38 cm (0.94 in). The mile ( Mil) is thus about 963 or 1146 meters (3160 or 3760 ft ...
The link (usually abbreviated as "l.", "li." or "lnk."), sometimes called a Gunter’s link, is a unit of length formerly used in many English-speaking countries. In US customary units modern definition, the link is exactly 66100 of a US survey foot, [1] or exactly 7.92 inches or approximately 20.12 cm. The unit is based on Gunter's chain, a ...
A teleconverter (sometimes called tele extender) is a secondary lens mounted between a camera and a photographic lens which enlarges the central part of an image obtained by the lens. For example, a 2× teleconverter for a 35 mm camera enlarges the central 12×18 mm part of an image to the size of 24×36 mm in the standard 35 mm film format .
30.48 cm. 304.8 mm. The foot ( pl. feet; standard symbol: ft) [1] [2] is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, ′, is commonly used to represent the foot. [3] In both customary and imperial units, one foot comprises 12 inches, and one yard comprises three feet.