What is Photoelectric current: Definition and 11 Discussions

The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission.
The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's intensity or duration of exposure. Because a low-frequency beam at a high intensity could not build up the energy required to produce photoelectrons like it would have if light's energy was coming from a continuous wave, Albert Einstein proposed that a beam of light is not a wave propagating through space, but a swarm of discrete energy packets, known as photons.
Emission of conduction electrons from typical metals requires a few electron-volt (eV) light quanta, corresponding to short-wavelength visible or ultraviolet light. In extreme cases, emissions are induced with photons approaching zero energy, like in systems with negative electron affinity and the emission from excited states, or a few hundred keV photons for core electrons in elements with a high atomic number. 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. Other phenomena where light affects the movement of electric charges include the photoconductive effect, the photovoltaic effect, and the photoelectrochemical effect.

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  1. R

    I Some questions about the photoelectric experiment

    Background: self-studying. Very confused. Here are some initial questions I have about the photoelectric experiment. Some more may pop up later. 1. The book says we know photons exist due to energy considerations (such as emission or absorption). They also say that this photon energy is...
  2. J

    Photoelectric current and a convex lens

    Homework Statement Homework EquationsThe Attempt at a Solution The photoelectric current is directly proportional to the intensity of the light falling on it . It will not depend on the focal length of the lens . When the lens of half the diameter is used , intensity is halved . This...
  3. F

    Saturation voltage for photoelectric current

    Hi, I was wondering about saturation current in the photoelectric effect. It is clear to me that for a sufficiently large accelerating potential all of the electrons are gathered by the collecting electrode. Since it is all of them, there cannot be more, and the current won't change if the...
  4. Supitha

    B 2 questions about the photo electric effect

    How can explain the difference of these red dots? Red line = Green line ?. How to explain it?
  5. M

    Photoelectron to electron hole pair doubts

    Hi, I have a couple of questions on photoelectrons. When a photoelectron of about 3-eV (varies) interacts within 0.2-um depletion region of silicon, what happens? I know, it will generate an electron-hole pair with an efficiency of 1 for 3.6-eV photoelectron. But what happens if the...
  6. B

    Photoelectric current: why does it decrease?

    In my book it is stated.When you keep the intensity constant and decrease the wavelength the photoelectric current decreases but I can't understand why? I thought it would stay the same since photoelectric current depends on the intensity of photons as more number oh photons means more e- released
  7. Salvador

    Calculating Photoelectric Current in Amps

    Hi, how could i calculate the current I would get from the photoelectric effect, so that the end result would be in amps? If I have a certain lightsource or source of powerful enough em radiation to conduct the photoelectric effect , how could I calculate the intensity needed for given current ...
  8. G

    Calculating Max Electric Current in Photoelectric Cell

    Hi. The problem is the following: I have 2.5×10^{15} photons inciding every second on a photoelectric cell. Each photon has 2.5eV of energy and the work function of the cell is 2.2eV. I know that the photoelectric conversion efficiency is 20% and I'm asked to find the maximum electric current...
  9. R

    Effect of resistance on photoelectric current

    Homework Statement Mmmm... Me and my classmate came across with this problem when studying photoelectric effect... Given a photocell connected to a circuit with a variable resistor (with resistance R) and an ideal ammeter. When a monochromatic light with frequency (f) (f>f0) and intensity...
  10. I

    Photoelectric current VS frequency

    Hello All, I have a problem that has been troubling me and I have been unable to find an answer on Google. It is said that 1 photon = 1 photoelectron ejected, Therefore the photoelectric current produced is directly proportional to the intensity of light used. It is also said that the frequency...
  11. L

    Photoelectric current equation

    Homework Statement In Lenard's experiment to determine e/m for photoelectrons, he puts forwards this equation mv2/2 = eV, where e is the charge, m is the mass of photoelectron, and V is the potential applied. Why the kinetic energy equation is equated to eV? Thanks in advance Homework...