group index - перевод на русский
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group index - перевод на русский

RATIO OF THE SPEED OF LIGHT IN VACUUM TO THAT IN THE MEDIUM
Index of refraction; Refractive indices; Complex index of refraction; Index of Refraction; Refraction index; Refracting index; Refractivity; Refractive Index; Negative index of refraction; Index Of Refraction; Absolute refractive index; Optical extinction coefficient; Complex refractive index; Group index

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американизм

индекс группы, групповой индекс (грунтов)

group index         
group index         
амер.
индекс группы, групповой индекс (грунтов)

Определение

митотический индекс
показатель митотической активности ткани или культуры ткани, представляющий собой число делящихся путем митоза клеток из 1000 изученных на гистологическом препарате.

Википедия

Refractive index

In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.

The refractive index determines how much the path of light is bent, or refracted, when entering a material. This is described by Snell's law of refraction, n1 sin θ1 = n2 sin θ2, where θ1 and θ2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices n1 and n2. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity (Fresnel's equations) and Brewster's angle.

The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is v = c/n, and similarly the wavelength in that medium is λ = λ0/n, where λ0 is the wavelength of that light in vacuum. This implies that vacuum has a refractive index of 1, and assumes that the frequency (f = v/λ) of the wave is not affected by the refractive index.

The refractive index may vary with wavelength. This causes white light to split into constituent colors when refracted. This is called dispersion. This effect can be observed in prisms and rainbows, and as chromatic aberration in lenses. Light propagation in absorbing materials can be described using a complex-valued refractive index. The imaginary part then handles the attenuation, while the real part accounts for refraction. For most materials the refractive index changes with wavelength by several percent across the visible spectrum. Nevertheless, refractive indices for materials are commonly reported using a single value for n, typically measured at 633 nm.

The concept of refractive index applies across the full electromagnetic spectrum, from X-rays to radio waves. It can also be applied to wave phenomena such as sound. In this case, the speed of sound is used instead of that of light, and a reference medium other than vacuum must be chosen.

For lenses (such as eye glasses), a lens made from a high refractive index material will be thinner, and hence lighter, than a conventional lens with a lower refractive index. Such lenses are generally more expensive to manufacture than conventional ones.

Примеры употребления для group index
1. Manufactured Products group index declined by 0.1 per cent to 178 points due to cheaper chemicals, cement and machinery.
2. Manufacturing Products group index declined by 0.2 per cent to 180.5 points as prices eased for food products, textiles and basic metals.
3. Textiles group index declined by 0.4 per cent to 132 points due to lower prices of polyster staple fibre (7 per cent) and acrylic yarn (1 per cent). Chemicals and Chemical Products group index was up by 0.1 per cent to 1'4.1 points due to higher prices of powder other than vitamins (11 per cent) and phenol (3 per cent), but liquid chlorine became cheaper by 1 per cent.
4. Basic Metals Alloys and Metal Products group index declined marginally by 0.04 per cent to 238.6 points due to lower prices of pipes and tubes (2 per cent), even as lead ingots became costlier by 4 per cent.
5. Food articles group index declined marginally during the week, mainly driven by lower prices of tea, barley and fruits and vegetables that fell by four per cent, three per cent and one per cent respectively.
Примеры по www.pressmon.com
Как переводится group index на Русский язык