A report on Light

A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.
The electromagnetic spectrum, with the visible portion highlighted
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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.
Pierre Gassendi.
Christiaan Huygens.
Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.
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Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

- Light
A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.

81 related topics with Alpha

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Fig. 1: Schematic diagram of Compton's experiment. Compton scattering occurs in the graphite target on the left. The slit passes X-ray photons scattered at a selected angle. The energy of a scattered photon is measured using Bragg scattering in the crystal on the right in conjunction with ionization chamber; the chamber could measure total energy deposited over time, not the energy of single scattered photons.

Compton scattering

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Scattering of a high frequency photon after an interaction with a stationary charged particle, usually an electron.

Scattering of a high frequency photon after an interaction with a stationary charged particle, usually an electron.

Fig. 1: Schematic diagram of Compton's experiment. Compton scattering occurs in the graphite target on the left. The slit passes X-ray photons scattered at a selected angle. The energy of a scattered photon is measured using Bragg scattering in the crystal on the right in conjunction with ionization chamber; the chamber could measure total energy deposited over time, not the energy of single scattered photons.
Fig. 3: Energies of a photon at 500 keV and an electron after Compton scattering.

At energies of a few eV to a few keV, corresponding to visible light through soft X-rays, a photon can be completely absorbed and its energy can eject an electron from its host atom, a process known as the photoelectric effect.

Roger Bacon

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Medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiricism.

Medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiricism.

The memorial to Roger Bacon at St Mary Major, Ilchester
A diorama of Bacon presenting one of his works to the chancellors of Paris University
A 19th-century engraving of Bacon observing the stars at Oxford
Ernest Board's portrayal of Bacon in his observatory at Merton College
A manuscript illustration of Bacon presenting one of his works to the chancellor of the University of Paris
Optic studies by Bacon
Bacon's diagram of light being refracted by a spherical container of water
"Roger Bacon discovers gunpowder", "whereby Guy Fawkes was made possible", an image from Bill Nye's Comic History of England
Friar Bacon in his study
A 19th-century etching of Bacon conducting an alchemical experiment
A portrait of Roger Bacon from a 15th-century edition of De Retardatione
The first page of the letter from Bacon to Clement IV introducing his Opus Tertium
A woodcut from Robert Greene's play displaying the brazen head pronouncing "Time is. Time was. Time is past."
"Friar Bacon's Study" in Oxford. By the late 18th century this study on Folly Bridge had become a place of pilgrimage for scientists, but the building was pulled down in 1779 to allow for road widening.
The Westgate plaque at Oxford
William Blake's visionary head of "Friar Bacon"
alt=|Spine of a 1750 edition of Opus majus
alt=|Title page of 1750 edition of Opus majus
alt=|First page of 1750 edition of Opus majus

In Part V of the Opus Majus, Bacon discusses physiology of eyesight and the anatomy of the eye and the brain, considering light, distance, position, and size, direct and reflected vision, refraction, mirrors, and lenses.

Illustration of a simple (plane) transverse wave propagating through an elastic medium in the horizontal direction, with particles being displaced in the vertical direction. Only one layer of the material is shown

Transverse wave

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Wave whose oscillations are perpendicular to the direction of the wave's advance.

Wave whose oscillations are perpendicular to the direction of the wave's advance.

Illustration of a simple (plane) transverse wave propagating through an elastic medium in the horizontal direction, with particles being displaced in the vertical direction. Only one layer of the material is shown
Illustration of the electric (red) and magnetic (blue) fields along a ray in a simple light wave. For any plane perpendicular to the ray, each field has always the same value at all points of the plane.
Propagation of a transverse spherical wave in a 2d grid (empirical model)
Circular polarization mechanically generated on a rubber thread, converted to linear polarization by a mechanical polarizing filter.

Light is another example of a transverse wave, where the oscillations are the electric and magnetic fields, which point at right angles to the ideal light rays that describe the direction of propagation.

Étienne-Louis Malus

Étienne-Louis Malus

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French officer, engineer, physicist, and mathematician.

French officer, engineer, physicist, and mathematician.

Étienne-Louis Malus

His mathematical work was almost entirely concerned with the study of light.

Figures 1 and 2 in A Preliminary communication on the pressure of heat and light radiation, Phys. Rev. 13, 307-320 (1901).

Nichols radiometer

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The apparatus used by Ernest Fox Nichols and Gordon Ferrie Hull in 1901 for the measurement of radiation pressure.

The apparatus used by Ernest Fox Nichols and Gordon Ferrie Hull in 1901 for the measurement of radiation pressure.

Figures 1 and 2 in A Preliminary communication on the pressure of heat and light radiation, Phys. Rev. 13, 307-320 (1901).

A beam of light was directed first on one mirror and then on the other, and the opposite deflections observed with mirror and scale.

Schematic of photosynthesis in plants. The carbohydrates produced are stored in or used by the plant.

Photosynthesis

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Process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities.

Process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities.

Schematic of photosynthesis in plants. The carbohydrates produced are stored in or used by the plant.
Composite image showing the global distribution of photosynthesis, including both oceanic phytoplankton and terrestrial vegetation. Dark red and blue-green indicate regions of high photosynthetic activity in the ocean and on land, respectively.
Photosynthesis changes sunlight into chemical energy, splits water to liberate O2, and fixes CO2 into sugar.
Light-dependent reactions of photosynthesis at the thylakoid membrane
The "Z scheme"
Overview of the Calvin cycle and carbon fixation
Overview of C4 carbon fixation
Plant cells with visible chloroplasts (from a moss, Plagiomnium affine)
Portrait of Jan Baptist van Helmont by Mary Beale, c.1674
Melvin Calvin works in his photosynthesis laboratory.
The leaf is the primary site of photosynthesis in plants.
Absorbance spectra of free chlorophyll a ( blue ) and b ( red ) in a solvent. The action spectra of chlorophyll molecules are slightly modified in vivo depending on specific pigment–protein interactions.
Photorespiration

The surface of the leaf is coated with a water-resistant waxy cuticle that protects the leaf from excessive evaporation of water and decreases the absorption of ultraviolet or blue light to minimize heating.

First prototype ammonia maser and inventor Charles H. Townes. The ammonia nozzle is at left in the box, the four brass rods at center are the quadrupole state selector, and the resonant cavity is at right. The 24 GHz microwaves exit through the vertical waveguide Townes is adjusting. At bottom are the vacuum pumps.

Maser

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Device that produces coherent electromagnetic waves through amplification by stimulated emission.

Device that produces coherent electromagnetic waves through amplification by stimulated emission.

First prototype ammonia maser and inventor Charles H. Townes. The ammonia nozzle is at left in the box, the four brass rods at center are the quadrupole state selector, and the resonant cavity is at right. The 24 GHz microwaves exit through the vertical waveguide Townes is adjusting. At bottom are the vacuum pumps.
A hydrogen radio frequency discharge, the first element inside a hydrogen maser (see description below)
A hydrogen maser.

Gould originally proposed distinct names for devices that emit in each portion of the spectrum, including grasers (gamma ray lasers), xasers (x-ray lasers), uvasers (ultraviolet lasers), lasers (visible lasers), irasers (infrared lasers), masers (microwave masers), and rasers (RF masers).

Cover of Vitellonis Thuringopoloni opticae libri decem (Ten Books of Optics by the Thuringo-Pole Witelo)

Vitello

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Friar, theologian, natural philosopher and an important figure in the history of philosophy in Poland.

Friar, theologian, natural philosopher and an important figure in the history of philosophy in Poland.

Cover of Vitellonis Thuringopoloni opticae libri decem (Ten Books of Optics by the Thuringo-Pole Witelo)
Page from a manuscript of De Perspectiva, with miniature of its author Vitello

Light itself is, for Vitello, the first of all sensible entities, and his views on light are similar to those held by Roger Bacon, though he is closer in this to Alhazen's legacy.

Francesco Maria Grimaldi

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Italian Jesuit priest, mathematician and physicist who taught at the Jesuit college in Bologna.

Italian Jesuit priest, mathematician and physicist who taught at the Jesuit college in Bologna.

He was the first to make accurate observations on the diffraction of light (although by some accounts Leonardo da Vinci had earlier noted it ), and coined the word 'diffraction'.

Dispersion relation of phonon polaritons in GaP. Red curves are the uncoupled phonon and photon dispersion relations, black curves are the result of coupling (from top to bottom: upper polariton, LO phonon, lower polariton).

Polariton

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Electric or magnetic dipole-carrying excitation.

Electric or magnetic dipole-carrying excitation.

Dispersion relation of phonon polaritons in GaP. Red curves are the uncoupled phonon and photon dispersion relations, black curves are the result of coupling (from top to bottom: upper polariton, LO phonon, lower polariton).

In February 2018, scientists reported the discovery of a new three-photon form of light, which may involve polaritons, that could be useful in the development of quantum computers.