Spectrum and Related Topics

Electromagnetic spectrum

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A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths

Plot of Earth's atmospheric opacity to various wavelengths of electromagnetic radiation. This is the surface-to-space opacity, the atmosphere is transparent to longwave radio transmissions within the troposphere but opaque to space due to the ionosphere.

Plot of atmospheric opacity for terrestrial to terrestrial transmission showing the molecules responsible for some of the resonances

The amount of penetration of UV relative to altitude in Earth's ozone

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.

An example of spectroscopy: a prism analyses white light by dispersing it into its component colors.

General field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation.

$A huge diffraction grating at the heart of the ultra-precise ESPRESSO spectrograph.$

UVES is a high-resolution spectrograph on the Very Large Telescope.

Spectroscopy is a branch of science concerned with the spectra of electromagnetic radiation as a function of its wavelength or frequency measured by spectrographic equipment, and other techniques, in order to obtain information concerning the structure and properties of matter.

Light

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Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

The electromagnetic spectrum, with the visible portion highlighted

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily

$Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.$

Hong Kong illuminated by colourful artificial lighting.

$Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.$

The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization.

Wavelength

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Spatial period of a periodic wave—the distance over which the wave's shape repeats.

Sinusoidal standing waves in a box that constrains the end points to be nodes will have an integer number of half wavelengths fitting in the box.

A standing wave (black) depicted as the sum of two propagating waves traveling in opposite directions (red and blue)

Wavelength is decreased in a medium with slower propagation.

$Refraction: upon entering a medium where its speed is lower, the wave changes direction.$

Separation of colors by a prism (click for animation)

Various local wavelengths on a crest-to-crest basis in an ocean wave approaching shore

A sinusoidal wave travelling in a nonuniform medium, with loss

A wave on a line of atoms can be interpreted according to a variety of wavelengths.

Wavelength of a periodic but non-sinusoidal waveform.

Pattern of light intensity on a screen for light passing through two slits. The labels on the right refer to the difference of the path lengths from the two slits, which are idealized here as point sources.

$Diffraction pattern of a double slit has a single-slit envelope.$

Relationship between wavelength, angular wavelength, and other wave properties.

The range of wavelengths or frequencies for wave phenomena is called a spectrum.

Spectrometer

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Spectrum of light emitted by a deuterium lamp in the UV, visible and near infrared part of the electromagnetic spectrum.

A positive charged particle moving in a circle under the influence of the Lorentz force F

Focus of a magnetic semicircular spectrometer

A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon.

Replica of J.J. Thomson's third mass spectrometer

Mass spectrometry

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Analytical technique that is used to measure the mass-to-charge ratio of ions.

Calutron mass spectrometers were used in the Manhattan Project for uranium enrichment.

Schematics of a simple mass spectrometer with sector type mass analyzer. This one is for the measurement of carbon dioxide isotope ratios (IRMS) as in the carbon-13 urea breath test.

Surface ionization source at the Argonne National Laboratory linear accelerator

Quadrupole mass spectrometer and electrospray ion source used for Fenn's early work

ThermoQuest AvantGarde sector mass spectrometer

Fourier-transform ion cyclotron resonance mass spectrometer

A continuous dynode particle multiplier detector

Tandem mass spectrometry for biological molecules using ESI or MALDI

A gas chromatograph (right) directly coupled to a mass spectrometer (left)

Indianapolis Museum of Art conservation scientist performing liquid chromatography–mass spectrometry

Mass spectrum of a peptide showing the isotopic distribution

Toluene electron ionization mass spectrum

NOAA Particle Analysis by Laser Mass Spectrometry aerosol mass spectrometer aboard a NASA WB-57 high-altitude research aircraft

Mass spectrometer to determine the 16O/18O and 12C/13C isotope ratio on biogenous carbonate

NASA's Phoenix Mars Lander analyzing a soil sample from the "Rosy Red" trench with the TEGA mass spectrometer

Early spectrometry devices that measured the mass-to-charge ratio of ions were called mass spectrographs which consisted of instruments that recorded a spectrum of mass values on a photographic plate.

Portrait of Newton at 46 by Godfrey Kneller, 1689

Isaac Newton

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English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the greatest mathematicians and physicists of all time and among the most influential scientists.

Replica of Newton's second reflecting telescope, which he presented to the Royal Society in 1672

Illustration of a dispersive prism separating white light into the colours of the spectrum, as discovered by Newton

Facsimile of a 1682 letter from Isaac Newton to Dr William Briggs, commenting on Briggs' A New Theory of Vision.

Engraving of a Portrait of Newton by John Vanderbank

Newton's own copy of his Principia, with hand-written corrections for the second edition, in the Wren Library at Trinity College, Cambridge.

Isaac Newton in old age in 1712, portrait by Sir James Thornhill

Coat of arms of the Newton family of Great Gonerby, Lincolnshire, afterwards used by Sir Isaac.

Newton's tomb monument in Westminster Abbey

A Wood engraving of Newton's famous steps under the apple tree.

Newton statue on display at the Oxford University Museum of Natural History

Newton (1795, detail) by William Blake. Newton is depicted critically as a "divine geometer".

During this period he investigated the refraction of light, demonstrating that the multicoloured image produced by a prism, which he named a spectrum, could be recomposed into white light by a lens and a second prism.

Continuum (measurement)

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Continuum theories or models explain variation as involving gradual quantitative transitions without abrupt changes or discontinuities.

A spectrum in physics, such as the electromagnetic spectrum, is often termed as either continuous (with energy at all wavelengths) or discrete (energy at only certain wavelengths).

Rainbow

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Meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky.