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A diagram illustrating the emission of electrons from a metal plate, requiring energy gained from an incoming photon to be more than the work function of the material.
A diagram illustrating the emission of electrons from a metal plate, requiring energy gained from an incoming photon to be more than the work function of the material.
Low energy phenomena Photoelectric effect
Mid-energy phenomena Compton scattering
High energy phenomena Pair production

The photoelectric effect is a quantum electronic phenomenon in which electrons are emitted from matter after the absorption of energy from electromagnetic radiation such as x-rays or visible light. The Compton shift formula Klein-Nishina formulaCompton used a combination of three fundamental formulas representing the various aspects of classical and modern physics combining See also Electron-positron annihilation Meitner–Hupfeld effect Pair instability supernova Quantum electrodynamics ( QED) is a relativistic Quantum field theory of Electrodynamics. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. X-radiation (composed of X-rays) is a form of Electromagnetic radiation. [1] The emitted electrons can be referred to as photoelectrons in this context. The effect is also termed the Hertz Effect,[2][3] due to its discovery by Heinrich Rudolf Hertz, although the term has generally fallen out of use. Heinrich Rudolf Hertz ( February 22, 1857 – January 1, 1894) was a German physicist who clarified and expanded the electromagnetic theory

Study of the photoelectric effect led to important steps in understanding the quantum nature of light and electrons and influenced the formation of the concept of wave–particle duality. In Physics and Chemistry, wave–particle duality is the concept that all Matter and Energy exhibits both Wave -like and [1]

The term may also refer to the photoconductive effect (also known as photoconductivity or photoresistivitity), the photovoltaic effect, or the photoelectrochemical effect. Photoconductivity is an optical and electrical phenomenon in which a material becomes more conductive due to the absorption of electro-magnetic radiation A photoresistor or Light Dependent Resistor or CdS Cell is a Resistor whose resistance decreases with increasing incident light intensity A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. Photoelectrochemical cells or PECs are Solar cells and extract electrical energy from light including Visible light.

Contents

Introduction

When a metallic surface is exposed to electromagnetic radiation above a certain threshold frequency, the light is absorbed and electrons are emitted. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. Frequency is a measure of the number of occurrences of a repeating event per unit Time. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J In 1902, Philipp Eduard Anton von Lenard observed that the energy of the emitted electrons increased with the frequency, or colour, of the light. Philipp Eduard Anton von Lénárd ( June 7, 1862 &ndash May 20, 1947) was a German physicist and the winner of the In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός This was at odds with James Clerk Maxwell's wave theory of light, which predicted that the energy would be proportional to the intensity of the radiation. James Clerk Maxwell (13 June 1831 &ndash 5 November 1879 was a Scottish mathematician and theoretical physicist. In Physics, intensity is a measure of the time-averaged Energy Flux. In 1905, Einstein solved this paradox by describing light as composed of discrete quanta, now called photons, rather than continuous waves. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Based upon Max Planck's theory of black-body radiation, Einstein theorized that the energy in each quantum of light was equal to the frequency multiplied by a constant, later called Planck's constant. The Electromagnetic radiation emitted by a Black body. You may also be looking for Incandescence, the radiation from a body The Planck constant (denoted h\ is a Physical constant used to describe the sizes of quanta. A photon above a threshold frequency has the required energy to eject a single electron, creating the observed effect. This discovery led to the quantum revolution in physics and earned Einstein the Nobel Prize in 1921. The Nobel Prize in Physics (Nobelpriset i fysik is awarded once a year by the Royal Swedish Academy of Sciences.

Explanation

The photons of the light beam have a characteristic energy determined by the frequency of the light. In the photoemission process, if an electron absorbs the energy of one photon and has more energy than the work function, it is ejected from the material. In Solid state physics, the work function is the minimum Energy (usually measured in Electron volts needed to remove an Electron from a solid If the photon energy is too low, the electron is unable to escape the surface of the material. Increasing the intensity of the light beam does not change the energy of the constituent photons, only the number of photons. Thus the energy of the emitted electrons does not depend on the intensity of the incoming light, but only on the energy of the individual photons.

Electrons can absorb energy from photons when irradiated, but they follow an "all or nothing" principle. All of the energy from one photon must be absorbed and used to liberate one electron from atomic binding, or the energy is re-emitted. If the photon energy is absorbed, some of the energy liberates the electron from the atom, and the rest contributes to the electron's kinetic energy as a free particle. The kinetic energy of an object is the extra Energy which it possesses due to its motion

Laws of photoelectric emission

  1. For a given metal and frequency of incident radiation, the rate at which photoelectrons are ejected is directly proportional to the intensity of the incident light.
  2. For a given metal, there exists a certain minimum frequency of incident radiation below which no photoelectrons can be emitted. This frequency is called the threshold frequency.
  3. Above the threshold frequency, the maximum kinetic energy of the emitted photoelectron is independent of the intensity of the incident light but depends on the frequency of the incident light.
  4. The time lag between the incidence of radiation and the emission of a photoelectron is very small, less than 10-9 second.

Equations

In analyzing the photoelectric effect quantitatively using Einstein's method, the following equivalent equations are used:

Energy of photon = Energy needed to remove an electron + Kinetic energy of the emitted electron

Algebraically:

hf = \phi + E_{k_{max}} \,

where

Since an emitted electron cannot have negative kinetic energy, the equation implies that if the photon's energy (hf) is less than the work function (φ), no electron will be emitted.

According to Einstein's special theory of relativity the relation between energy (E) and momentum (p) of a particle is E = \sqrt{(pc)^2 + (mc^2)^2}, where m is the rest mass of the particle and c is the velocity of light in a vacuum.

Three-step model

The photoelectric effect in crystalline material is often decomposed into three steps:[4]

  1. Inner photoelectric effect (see photodiode below). The hole left behind can give rise to auger effect, which is visible even when the electron does not leave the material. The Auger effect (ˈɔːʒɚ or Oh' jeh is a phenomenon in Physics in which the emission of an Electron from an Atom causes the emission of a second In molecular solids photons are excited in this step and may be visible as lines in the final electron energy. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena The inner photoeffect has to be dipole allowed. The transition rules for atoms translate via the tight-binding model onto the crystal. Transition rule is a non-standard and rarely used name for Selection rule, as applied to radiative transitions. In the tight binding model for a solid-state lattice of atoms it is assumedthat the full Hamiltonian H of the system may be approximated by theHamiltonian of an isolated They are similar in geometry to plasma oscillations in that they have to be transversal. Plasma oscillations, also known as " Langmuir waves " (after Irving Langmuir) are rapid oscillations of the electron density in conducting media such as
  2. Ballistic transport of half of the electrons to the surface. Some electrons are scattered.
  3. Electrons escape from the material at the surface.

In the three-step model, an electron can take multiple paths through these three steps. All paths can interfere in the sense of the path integral formulation. This article is about a formulation of quantum mechanics For integrals along a path also known as line or contour integrals see Line integral. For surface states and molecules the three-step model does still make some sense as even most atoms have multiple electrons which can scatter the one electron leaving. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny

History

Early observations

In 1839, Alexandre Edmond Becquerel observed the photoelectric effect via an electrode in a conductive solution exposed to light. Alexandre-Edmond Becquerel ( March 24, 1820 - May 11, 1891) was a French Physicist who studied the Solar spectrum In 1873, Willoughby Smith found that selenium is photoconductive. Year 1873 ( MDCCCLXXIII) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common Willoughby Smith ( April 6, 1828, Great Yarmouth, Norfolk — July 17, 1891, Eastbourne, Sussex) was Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78

Hertz's spark gaps

In 1887, Heinrich Hertz observed the photoelectric effect and the production and reception of electromagnetic (EM) waves. Heinrich Rudolf Hertz ( February 22, 1857 – January 1, 1894) was a German physicist who clarified and expanded the electromagnetic theory He published these observations in the journal Annalen der Physik. Annalen der Physik is one of the best-known and oldest (since 1790 Physics journals worldwide His receiver consisted of a coil with a spark gap, where a spark would be seen upon detection of EM waves. A spark gap consists of an arrangement of two conducting Electrodes separated by a gap usually filled with a Gas such as Air. He placed the apparatus in a darkened box to see the spark better. However, he noticed that the maximum spark length was reduced when in the box. A glass panel placed between the source of EM waves and the receiver absorbed ultraviolet radiation that assisted the electrons in jumping across the gap. When removed, the spark length would increase. He observed no decrease in spark length when he substituted quartz for glass, as quartz does not absorb UV radiation. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Hertz concluded his months of investigation and reported the results obtained. He did not further pursue investigation of this effect, nor did he make any attempt at explaining how this phenomenon was brought about.

JJ Thomson: electrons

In 1899, J. J. Thomson investigated ultraviolet light in Crookes tubes. Sir Joseph John “JJ” Thomson, OM, FRS (18 December 1856 &ndash 30 August 1940 was a British Physicist and Nobel laureate Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays The Geissler tube is a glass tube for demonstrating the principles of electrical Glow discharge. Influenced by the work of James Clerk Maxwell, Thomson deduced that cathode rays consisted of negatively charged particles, later called electrons, which he called "corpuscles". James Clerk Maxwell (13 June 1831 &ndash 5 November 1879 was a Scottish mathematician and theoretical physicist. In the research, Thomson enclosed a metal plate (a cathode) in a vacuum tube, and exposed it to high frequency radiation. It was thought that the oscillating electromagnetic fields caused the atoms' field to resonate and, after reaching a certain amplitude, caused a subatomic "corpuscle" to be emitted, and current to be detected. The amount of this current varied with the intensity and color of the radiation. Larger radiation intensity or frequency would produce more current.

Radiant energy

Photoelectric motor, US685957Rays falling on insulated conductor connected to a capacitor: the capacitor charges electrically.
Photoelectric motor, US685957
Rays falling on insulated conductor connected to a capacitor: the capacitor charges electrically.

Nikola Tesla described the photoelectric effect in 1901. There have already been discussions about Tesla's ethnicity on the talk page Year 1901 ( MCMI) was a Common year starting on Tuesday (link will display calendar of the Gregorian calendar (or a Common year starting He described such radiation as vibrations of aether of small wavelengths which ionized the atmosphere. Vibration refers to mechanical Oscillations about an equilibrium point. In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " On November 5, 1901, he received the patent US685957 (Apparatus for the Utilization of Radiant Energy) that describes radiation charging and discharging conductors (e. Events 1499 - Publication of the Catholicon in Treguier ( Brittany) A patent is a set of Exclusive rights granted by a State to an inventor or his assignee for a fixed period of time in exchange for a disclosure of an Below is a list of Tesla patents. Dr Nikola Tesla was an Inventor who obtained around 300 Patents ref>Snezana Sarbo Tesla's Patents, Sixth g. , a metal plate or piece of mica) by "radiant energy". The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across The word "mica" is thought to be derived from the Latin word la micare, "glitteren" in reference to the brilliant appearance of this mineral (especially Radiant energy is the Energy of Electromagnetic waves The quantity of radiant energy may be calculated by integrating Radiant flux (or power Tesla used this effect to charge a capacitor with energy by means of a conductive plate (i. e. , a solar cell precursor). A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. The radiant energy threw off with great velocity minute particles (i. e. , electrons) which were strongly electrified. The patent specified that the radiation (or radiant energy) included many different forms. These devices have been referred to as "Photoelectric alternating current stepping motors".

In practice, a polished metal plate in radiant energy (e. g. sunlight) will gain a positive charge as electrons are emitted by the plate. As the plate charges positively, electrons form an electrostatic force on the plate (because of surface emissions of the photoelectrons), and "drain" any negatively charged capacitors. As the rays or radiation fall on the insulated conductor (which is connected to a capacitor), the condenser will indefinitely charge electrically. A capacitor is a passive electrical component that can store Energy in the Electric field between a pair of conductors

Von Lenard's observations

In 1902, Philipp Eduard Anton von Lenard observed the variation in electron energy with light frequency. Philipp Eduard Anton von Lénárd ( June 7, 1862 &ndash May 20, 1947) was a German physicist and the winner of the He used a powerful electric arc lamp which enabled him to investigate large changes in intensity, and had sufficient power to enable him to investigate the variation of potential with light frequency. His experiment directly measured potentials, not electron kinetic energy: he found the electron energy by relating it to the maximum stopping potential (voltage) in a phototube. He found that the calculated maximum electron kinetic energy is determined by the frequency of the light. The kinetic energy of an object is the extra Energy which it possesses due to its motion For example, an increase in frequency results in an increase in the maximum kinetic energy calculated for an electron upon liberation - ultraviolet radiation would require a higher applied stopping potential to stop current in a phototube than blue light. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays However Lenard's results were qualitative rather than quantitative because of the difficulty in performing the experiments: the experiments needed to be done on freshly cut metal so that the pure metal was observed, but it oxidised in a matter of minutes even in the partial vacuums he used. The current emitted by the surface was determined by the light's intensity, or brightness: doubling the intensity of the light doubled the number of electrons emitted from the surface. Lenard did not know of photons.

Einstein: light quanta

Albert Einstein's mathematical description in 1905 of how the photoelectric effect was caused by absorption of quanta of light (now called photons), was in the paper named "On a Heuristic Viewpoint Concerning the Production and Transformation of Light". Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena This paper proposed the simple description of "light quanta," or photons, and showed how they explained such phenomena as the photoelectric effect. His simple explanation in terms of absorption of single quanta of light explained the features of the phenomenon and the characteristic frequency. Einstein's explanation of the photoelectric effect won him the Nobel Prize in Physics in 1921. The Nobel Prize (Nobelpriset (Nobelprisen is a Swedish prize established in the 1895 will of Swedish chemist Alfred Nobel; it was first awarded in Peace, Literature

The idea of light quanta began with Max Planck's published law of black-body radiation ("On the Law of Distribution of Energy in the Normal Spectrum". For a general introduction see Black body. In Physics, Planck's law describes the spectral radiance of Electromagnetic radiation Annalen der Physik 4 (1901)) by assuming that Hertzian oscillators could only exist at energies E proportional to the frequency f of the oscillator by E = hf, where h is Planck's constant. By assuming that light actually consisted of discrete energy packets, Einstein wrote an equation for the photoelectric effect that fit experiments (it explained why the energy of the photoelectrons was dependent only on the frequency of the incident light and not on its intensity: a low intensity, high frequency source could supply a few high energy photons, whereas a high intensity, low frequency source would supply no photons of sufficient individual energy to dislodge any electrons). This was an enormous theoretical leap, and the reality of the light quanta was strongly resisted. The idea of light quanta contradicted the wave theory of light that followed naturally from James Clerk Maxwell's equations for electromagnetic behavior and more generally, the assumption of infinite divisibility of energy in physical systems. James Clerk Maxwell (13 June 1831 &ndash 5 November 1879 was a Scottish mathematician and theoretical physicist. The concept of infinite divisibility arises in different ways in Philosophy, Physics, Economics, Order theory (a branch of mathematics and Even after experiments showed that Einstein's equations for the photoelectric effect were accurate, resistance to the idea of photons continued, since it appeared to contradict Maxwell's equations, which were well understood and verified.

Einstein's work predicted that the energy of the ejected electrons increases linearly with the frequency of the light. Perhaps surprisingly, that had not yet been tested. In 1905 it was known that the energy of the photoelectrons increased with increasing frequency of incident light – and independent of the intensity of the light. However, the manner of the increase was not experimentally determined to be linear until 1915 when Robert Andrews Millikan showed that Einstein was correct. Robert Andrews Millikan (March 22 1868 – December 19 1953 was an American experimental physicist, and Nobel laureate in physics for his measurement [5]

Effect on wave–particle question

The photoelectric effect helped propel the then-emerging concept of the dualistic nature of light, that light exhibits characteristics of waves and particles at different times. Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 The effect was impossible to understand in terms of the classical wave description of light, as the energy of the emitted electrons did not depend on the intensity of the incident radiation. A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. Classical theory predicted that the electrons could 'gather up' energy over a period of time, and then be emitted. For such a classical theory to work a pre-loaded state would need to persist in matter. The idea of the pre-loaded state was discussed in Millikan's book Electrons (+ & –) and in Compton and Allison's book X-Rays in Theory and Experiment.

Uses and effects

Photodiodes and phototransistors

Solar cells (used in solar power) and light-sensitive diodes use a variant of the photoelectric effect, but not ejecting electrons out of the material. A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. Solar energy is the Light and radiant heat from the Sun that powers Earth 's Climate and Weather and sustains Life A photodiode is a type of Photodetector capable of converting Light into either current or Voltage, depending upon the mode of operation In semiconductors, light of even relatively low energy, such as visible photons, can kick electrons out of the valence band and into the higher-energy conduction band, where they can be harnessed, creating electric current at a voltage related to the bandgap energy. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that In Solids the valence band is the highest range of Electron energies where electrons are normally present at Absolute zero. In the Physics field of Semiconductors and insulators the conduction band is the range of Electron Energy, higher than that of the Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. In Solid state physics and related applied fields a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states

Image sensors

Video camera tubes in the early days of television used the photoelectric effect; newer variants used photoconductive rather than photoemissive materials. In older Video cameras before the mid to late 1980s a video camera tube or pickup tube was used instead of a Charge-coupled device (CCD Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic

Silicon image sensors, such as charge-coupled devices, widely used for photographic imaging, are based on a variant of the photoelectric effect, in which photons knock electrons out of the valence band of energy states in a semiconductor, but not out of the solid itself. An image sensor is a device that converts an optical image to an electric signal A charge-coupled device ( CCD) is an analog Shift register, that enables the transportation of analog signals (electric charges through successive stages (capacitors A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that

The Gold-leaf electroscope

The gold leaf electroscope.
The gold leaf electroscope.

Gold-leaf electroscopes are designed to detect static electricity. An electroscope is an early Scientific instrument that is used to detect the presence and magnitude of Electric charge on a body For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a Charge placed on the metal cap spreads to the stem and the gold leaf of the electroscope. Because they then have the same charge, the stem and leaf repel each other. This will cause the leaf to bend away from the stem.

The electroscope is an important tool in illustrating the photoelectric effect. Let us say that the scope is negatively charged throughout. There is an excess of electrons and the leaf is separated from the stem. But if we then shine high-frequency light onto the cap, the scope discharges and the leaf will fall limp. This is because the frequency of the light shining on the cap is above the cap's threshold frequency. The photons in the light have enough energy to liberate electrons from the cap, reducing its negative charge. This will discharge a negatively charged electroscope and further charge a positive electroscope.

However, if the EM radiation hitting the metal cap does not have a high enough frequency, (its frequency is below the threshold value for the cap) then the leaf will never discharge, no matter how long one shines the low-frequency light at the cap.

Photoelectron spectroscopy

Since the energy of the photoelectrons emitted is exactly the energy of the incident photon minus the material's work function or binding energy, the work function of a sample can be determined by bombarding it with a monochromatic X-ray source or UV source (typically a helium discharge lamp), and measuring the kinetic energy distribution of the electrons emitted. Monochrome comes from the Greek μονόχρωμος ( monochromos) meaning “of one color” which is a combination X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical

Photoelectron spectroscopy is done in a high vacuum environment, since the electrons would be scattered by air. Photoemission Spectroscopy (PES, also known as photoelectron spectroscopy, refers to energy measurement of electrons emitted from solids gases or liquids by the Photoelectric

A typical electron energy analyzer is a concentric hemispherical analyser (CHA), which uses an electric field to divert electrons different amounts depending on their kinetic energies. For every element and core (atomic orbital) there will be a different binding energy. The many electrons created from each will then show up as spikes in the analyzer, and can be used to determine the elemental composition of the sample.

Spacecraft

The photoelectric effect will cause spacecraft exposed to sunlight to develop a positive charge. A spacecraft is a Vehicle or machine designed for Spaceflight. This can get up to the tens of volts. The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. This can be a major problem, as other parts of the spacecraft in shadow develop a negative charge (up to several kilovolts) from nearby plasma, and the imbalance can discharge through delicate electrical components. The static charge created by the photoelectric effect is self-limiting, though, because a more highly-charged object gives up its electrons less easily. For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a [6]

Moon dust

Light from the sun hitting lunar dust causes it to become charged through the photoelectric effect. The charged dust then repels itself and lifts off the surface of the Moon by electrostatic levitation. Electrostatic levitation is the process of using an Electric field to lift a charged object and counteract the effects of Gravity. This manifests itself almost like an "atmosphere of dust", visible as a thin haze and blurring of distant features, and visible as a dim glow after the sun has set. This was first photographed by the Surveyor program probes in the 1960s. The Surveyor Program was a NASA program that from 1966 through 1968 sent seven Robotic spacecraft to the surface of the Moon. It is thought that the smallest particles are repelled up to kilometers high, and that the particles move in "fountains" as they charge and discharge. [7][8]

Night vision devices

Photons hitting a gallium arsenide plate in night vision devices cause the ejection of photoelectrons due to the photoelectric effect. A night vision device (NVD is an Optical instrument that allows images to be produced in levels of light approaching total darkness These are then amplified into a cascade of electrons that light up a phosphor screen. A phosphor is a substance that exhibits the phenomenon of Phosphorescence (sustained glowing after exposure to energized particles such as Electrons

References

Notes

  1. ^ a b Serway, Raymond A. (1990). Physics for Scientists & Engineers. Saunders, p. 1150. ISBN 0030302587.   Describes the photoelectric effect as the "emission of photoelectrons from matter", and describes the original usage as the "emission of photoelectrons from metallic surfaces" after the experiments of Milikan, and others.
  2. ^ The American journal of science. (1880). New Haven: J. D. & E. S. Dana. Page 234
  3. ^ Wolfram Scienceworld describes the terminology of the photoelectric effect and the previous usage of the term Hertz Effect.
  4. ^ Stefan Hüfner (2003). Photoelectron Spectroscopy: Principles and Applications. Springer. ISBN 3540418024.  
  5. ^ Einstein and the Photoelectric effect
  6. ^ Spacecraft charging
  7. ^ - Moon fountains
  8. ^ - Dust gets a charge in a vacuum

Book references

Serway, R. A. (1990). Physics for engineers and scientists, 3rd ed. Saunders Publishing

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Dictionary

photoelectric effect

-noun

  1. (physics) The emission of electrons from the surface of a material following the absorption of electromagnetic radiation
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