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The Munsell color system, showing: a circle of hues at value 5 chroma 6; the neutral values from 0 to 10; and the chromas of purple-blue (5PB) at value 5. In colorimetry , the Munsell color system is a color space that specifies colors based on three color dimensions: hue , value ( lightness ), and chroma (color purity). It was created by Professor Albert H.
The atmospheric attenuation of microwaves in dry air with a precipitable water vapor level of 0.001 mm. The downward spikes in the graph correspond to frequencies at which microwaves are absorbed more strongly. The right half of this graph includes the lower ranges of infrared by some standards Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz ) and 300 GHz. [ 1 ] [ 2 ] This broad definition includes both UHF and EHF ( millimeter waves ), and various sources use different boundaries. [ 3 ] In all cases, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower boundary at 1 GHz (30 cm), and the upper around 100 GHz (3 mm).
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz , and corresponding wavelengths ranging from 1 millimeter to 100 kilometers. Like all other electromagnetic waves, they travel at the speed of light . Naturally occurring radio waves are made by lightning , or by astronomical objects . Artificially generated radio waves are used for fixed and mobile radio communication , broadcasting , radar and other navigation systems, communications satellites , computer networks and innumerable other applications. Different frequencies of radio waves have different propagation characteristics in the Earth's atmosphere; long waves may cover a part of the Earth very consistently, shorter waves can reflect off the ionosphere and travel around the world, and much shorter wavelengths bend or reflect very little and travel on a line of sight.
Wavelength of a sine wave , λ, can be measured between any two points with the same phase , such as between crests, or troughs, or corresponding zero crossings as shown. In physics , the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats. [ 1 ] It is usually determined by considering the distance between consecutive corresponding points of the same phase , such as crests, troughs, or zero crossings , and is a characteristic of both traveling waves and standing waves , as well as other spatial wave patterns. [ 2 ] [ 3 ] Wavelength is commonly designated by the Greek letter lambda (λ). The concept can also be applied to periodic waves of non-sinusoidal shape. [ 1 ] [ 4 ] The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. [ 5 ] The SI unit of wavelength is the meter .
The electromagnetic waves that compose electromagnetic radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarized EMR wave propagating from left to right. The electric field is in a vertical plane and the magnetic field in a horizontal plane. The two types of fields in EMR waves are always in phase with each other, and no matter how powerful, have a ratio of electric to magnetic intensity which is fixed and never varies Electromagnetic radiation ( EM radiation or EMR ) is a form of energy emitted and absorbed by charged particles which exhibits wave-like behavior as it travels through space. EMR has both electric and magnetic field components, which stand in a fixed ratio of intensity to each other, and which oscillate in phase perpendicular to each other and perpendicular to the direction of energy and wave propagation .
Terahertz waves lie at the far end of the infrared band, just before the start of the microwave band. Terahertz ratiation is strongly absorbed by the atmosphere, limiting communication distance. The graph includes the lower part of the THz spectrum, from 0.3 to 1 THz. Shown is the zenith atmospheric transmission of electromagnetic radiation from space to the summit of Mauna Kea, assuming a precipitable water vapor level of 0.001 mm (simulated). The downward spikes in the graph correspond to strong absorption lines due to various absorbances of different atmospheric molecules
COLOUR MUSIC IN AUSTRALIA: De-mystifying De Maistre. COLOUR MUSIC IN THE NEW AGE: De-mystifying De Clario. MUSIC FOR MEASURE: On the Tercentenary of Newton's "Opticks".
The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye . Electromagnetic radiation in this range of wavelengths is called visible light or simply light . A typical human eye will respond to wavelengths from about 390 to 700 nm . [ 1 ] In terms of frequency, this corresponds to a band in the vicinity of 430–790 THz . A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function ). The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish.
The conventional seven colors of the rainbow symbol Natural rainbows typically do not show seven colors at all Roy G. Biv is an acronym for the sequence of hues commonly described as making up a rainbow : Red , Orange , Yellow , Green , Blue , Indigo and Violet . It is also known by the acronym, VIBGYOR , which gives the same colors in reverse order. A rainbow spans a continuous spectrum of colors; the distinct bands are an artifact of human color vision .