Photoelectric effect Definition and 395 Threads

  1. T

    Kinetic energy of recoil atom in the photoelectric effect

    Homework Statement In the photoelectric effect it is generalley assumed that all the energy is given as kinetic energy to the electron while the atom is neglected. Do not neglect the recoil kinetic energy of the atom and calculate the kinetic energy of the photoelectron and the ionized atom and...
  2. S

    How can I find the maximum KE of the photoelectrons?

    Homework Statement I don't know how to do Question 2 part C. Homework Equations I know that E=hf and I know the photoelectric equation: hf = work function + 1/2mv^2The Attempt at a Solution I honestly don't have a clue how to do part c of question 2. I think it involves one of the two...
  3. mertcan

    Photoelectric effect -- direction of the electron's trajectory

    Hi, I would like express that I really tried to dig something about the formula related to electron direction in photoelectric effect, but I could not find. Also I have seen that electron direction in photoelectric effect is not known according to some sites in internet. So, ıs it real that in...
  4. Z

    Photoelectric Effect, Light Intensity and Stopping Voltage

    In a physics investigation we were required to use a Photo-Electric Effect Instrument (Shown in the attached pdf file), which was able to measure the current produced via the photoelectric effect. One of the objectives of the investigation was to alter the aperture size, and hence intensity of...
  5. *now*

    Photoelectric effect calculation

    Photoelectric effect 1. Homework Statement A metal surface is illuminated with monochromatic light and it becomes charged to a steady positive potential of 1.0V relative to its surroundings. The work function energy of the metal surface is 3.0eV, the electron charge is 1.6 x 10-19 C. Calculate...
  6. R

    B About electrons and the photoelectric effect

    I understand that electrons can be released from a material, such as metal, through the photoelectric effect. I also understand that some of them might "re-attach" themselves to the metal. For practical uses, it sounds like the electrons would be re-captured in some way, but for the electrons...
  7. lawlieto

    I Are any electrons ejected below the threshold frequency?

    I've been reading about the photoelectric effect, and something got me thinking. If the frequency of light shone onto the metal is below the threshold frequency, no electrons are liberated from the surface of the metal, since electrons absorb quanta of energy, so if that light is shone for a...
  8. C

    Does the photoelectric effect eventually stop?

    Assume that a light shining on a metal initially resulted in electrons being emitted from the surface of the metal due to the photoelectric effect. If the light is left on indefinitely, will the emission of electrons eventually cease? (Assume the metal is insulated on all surfaces apart from the...
  9. C

    Interpreting I-V graphs in Photoelectric effect

    Homework Statement In photoelectric effect I-V graphs, for the same intensity but with different light frequencies (f2>f1), the I-V graph has the same max photocurrent but |Vs2| > |Vs1|. If we concentrate between the cutoff and the saturation regions of the I-V graph, we can see that at any...
  10. Biker

    Photoelectric Effect: The Impact of Light Intensity on Photocell Response

    Homework Statement If blue and red light are used on a photoelectric cell and they both have the same intensity (Power per area). Choose the correct option from the following Homework Equations E = nhf Intensity = power/area Quantum effeciency = 100% The Attempt at a Solution if they have...
  11. C

    Photoelectric effect : retarding potential with back current

    In the experiment of the determination of ##h## using the photoelectric effect produced by light emitted by led's there is the systematic problem of the "dark current" or "back current", i.e. the current caused by photoelectric effect on the anode of the system which is used in the expreriment...
  12. tom.stoer

    I Interpretation of the photoelectric effect

    The photoelectric effect is usually presented as an example disproving classical electromagnetism as viable model for interaction of light with matter and as evidence of quantization of energy in the electromagnetic field, i.e. the existence of photons. I would like to discuss a thought based on...
  13. A

    Photoelectric effect and zero time delay

    How does the zero time delay between illumination of light and emission of photo electron provides an evidence for the particle nature of light?
  14. U

    Photoelectric effect and bound electrons

    Hi. My question is why in photoelectric effect in coming photon interacts with bound electrons only? Thanks
  15. Ekramul Towsif

    Photoelectric Effect: X-ray, 2 Metals, 5 & 2.3eV Work Function

    Homework Statement X·ray is produced when an electron is incident on a metal surface with ##2x10^8 ms^-1## velocity .Applying this X-ray on the surface of two metals having work function of 5 eV and 2.3eV, photoelectric effect is observed. e by Homework Equations The Attempt at a Solution...
  16. G

    B Photoelectric effect and metal's delocalised electrons

    Hi all, With the photoelectric effect is it the 'sea' of free electrons that are ejected if the photons are above threshold frequency (i.e. Conduction band electrons ) rather than valence electrons ? If say very energetic gammas are used then suppose this could knock out valence electrons but...
  17. L

    Photoelectric Effect: Electron Flow Explained

    When the emitter is connected to the positive polarity of a battery, it is said that 'Some high speed electrons are still able to reach the collector and therefore there is flow of current.' (1) What is the flow of electrons like in this case? I thought electrons are supposed to flow from...
  18. C

    Photoelectric effect suddenly stopped working help

    my son did a duality of light science fair project .. did tons of work.. still likes doing the experiments at home anyway.. first off his wool and ebonite rod stopped putting a static charge on his christmas tree tinsle that he has on the end of a piece of a metal hanger sticking out of a metal...
  19. W

    Releasing Electrons with a color filter

    Homework Statement Simple question we have to answer: (Physics) How do I release the electrons from the cathode with a color filter? (The so called Photoelectric effect)Homework Equations none The Attempt at a Solution[/B] Here we have a conflict , the so called wave-particle duality, if...
  20. Bloopy

    B Einstein's Photoelectric Equation and its graph

    According to the equation, the graph of kinetic energy of emitted photoelectrons from a metal vs the frequency of incident radiation gives a straight line. My doubt is, what factors does the slope of this line depend on? I think it depends on the nature of metal used. Correct me if I am wrong.
  21. S

    Photoelectric effect find velocity?

    Homework Statement Light illuminates a metallic surface with work function of 1.20 eV. It takes 1.0 V of retarding potential to stop all of the photoelectrons from reaching the opposite plate. Find the maximum speed of the photoelectrons. Homework Equations hf = w hf = w + Ek The Attempt at...
  22. K

    I Photoelectric Effect: quantum energy doubts

    Hey, I've being studying the Photoelectric effect, I think I understand it superficially. One thing that has been bugging me is this: "Given that it is possible to move electrons with light and given that the energy in a beam of light is related to its intensity, classical physics would predict...
  23. P

    What properties of waves causes the photoelectric effect

    What properties of waves caused the photoelectric effect to indicate the fact that light was quantized. Why couldn't it be explained by light waves being emitted at the same frequency. I am a little confused about why light couldn't still be a wave. Couldn't the photoelectric effect be explained...
  24. Clara Chung

    Question about photoelectric effect?

    I think that an electron only absorb a photon with energy corresponding to the energy levels in an atom. If the energy of a photon is higher than the energy between a specific energy level and infinity level (0 eV), it can also absorb the photon and the remained energy is changed to KE. Am I...
  25. Metals

    B Photoelectric effect and atomic excitation

    A few quick questions I'd like cleared up:1) Alkali metals are said to have a really low threshold energy, enough for visible light to cause the photoelectric effect. Does this mean if I aim a flashlight (turned on) at a piece of sodium, I could ionise it? Simply flashing a light over a piece of...
  26. Elvis 123456789

    Question concerning photoelectric effect lab

    This isn't really a homework question but I do have to know it for my lab report so I figure this is a good place to post it. So for my lab we had the setup that is displayed in the picture attachments. My question deals specifically with step #9 of the lab instructions. I'm assuming that the...
  27. A

    Explaining the Photoelectric Effect: Why Can't Classical Electromagnetism Do It?

    I've read that the photoelectric effect cannot be explained according to Maxwell's equations and theory of electromagnetism. Classical EM theory treats light as a wave and states that the intensity of the light matters and not the frequency. According to Einstein, if we think of light as a...
  28. R

    Photoelectric Effect: Frequency vs. Amplitude

    How energy of the emitted electron is proportional to the incident light frequency but not to its amplitude according to photoelectric effect?
  29. A. Neumaier

    I History of the modeling of light

    That a quantum detector responds to classical light precisely according to Einstein's formulas for the photoeffect was already shown briefly in 1926 (the year the Schroedinger equation was born) by Wentzel, and was described in full detail in 1964 (when the development of the laser strongly...
  30. Vivan Vatsa

    Photoelectric Effect: Threshold Frequency Explained

    I have studied photoelectric effect. I have many doubts regarding that, so firstly, I cannot understand when, THRESHOLD FREQUENCY arises. " Threshold frequency is the frequency at which the electron gets ejected from the electrode & runs toward the other negatively charged electrode " , so my...
  31. Karan Punjabi

    Photoelectric Effect: Doubts Answered

    Hey I have a doubt that when on a metal surface photon falls then electrons are ripped off if the photon has frequency equal to or more than threshold frequency but photon falling on electron has a downward momentum and elctron rips off in a upward momentum...how is it possible according to law...
  32. EngPhy

    A Effect of visible light on conductivity

    Are metals better conductors in the presence of visible light? Considering photons in visible spectrum are not energetic enough to induce emission from a metal surface but they do cause the ejection of 'conduction electrons' which are bound to the metal by a few electron volts.
  33. CJit

    I Question on photoelectric effect and this particular experim

    question is based on the video above (1.5 mins). The main question is this, if photoelectrons are released based on the frequency of light that hits it, why is it that there is a large difference on the multimeter between when there is no filter, and when the blue filter is used (small...
  34. Dr. Manoj

    Why Is the Photoelectric Effect Considered Proof of Light's Particle Nature?

    I've a doubt regarding photoelectric effect. It's said that photoelectric effect is proof for light to be a particle. But, when seen into the theory, relations between wavelength and kinetic energy, frequency and photoelectric current are explained. The means we have used wave characters like...
  35. 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?
  36. JulienB

    Photoelectric effect at wavelength 492nm for mercury

    Homework Statement Hi everybody! I just did the photoelectric experiment this week, and I have a report to write about it. We used a mercury vapour lamp, a set of metal interference filters and a grey filter in order to find the intersection point (and therefore ##U_{g,max}## between the...
  37. S

    Calculating Stopping Potential in Photoelectric Effect Experiment

    Homework Statement In a photoelectric experiment, a stopping potential of 2.70 eV is measured when ultraviolet light of wavelength 380 nm is incident on the metal. If blue light of wavelength 440 nm is used, what is the new stopping potential in eV? Homework EquationsThe Attempt at a...
  38. NihalRi

    Find current induced in the photoelectric effect

    Homework Statement A metal surface had dimensions of 1.5mm x 2mm. The intensity of light incident on surface is 4.5×10^-6 W/m^2. On average one electron is emitted for every 300 photons incident on the surface. Determine the initial current leaving the metal. ●wavelength of light incident is...
  39. Polly812

    I Does photoelectric effect include light with threshold freq?

    I know the definition of photoelectric effect : the release of electrons from a metal when it is in contact with electromagnetic waves.. However, my question is.. If a light wave hits a metal and that photon has freq = threshold frequency of that metal, does this mean that the energy of the...
  40. Karan Punjabi

    Photoelectric Effect: Metal Electron Bonding Explained

    Guys I'm understand this effect but understanding it i got a practical doubt that though the bond(metallic bond) between metal atoms is very strong then too electrons are easily ripped of compared to other elements I know metals have free electrons but they are strongly bonded to the atoms then...
  41. D

    B Photoelectric Effect under cutoff frequency

    I understand the concepts of photoelectric effect where an electron will be emitted when a photon with sufficient energy collides with it. There are two parts to this question, 1. What happens during the collision? Is the photon absorbed by the photoelectron wholly as energy? 2. If so...
  42. Docscientist

    Photoelectric effect and free electrons

    When we shine a light of particular color on a metal,it expells the free electrons present in the metal.In that case,doesn't the metal get ionized ?
  43. G

    B Explain Photoelectric Effect: Potential, Formula & Voltage

    Can someone explain what is stopping potenial is and can explain the formula : e × Vs. Does the v stand for voltage
  44. N

    Electron ejected in Photoelectric effect

    Since the binding energy of an electron in outer shell is smaller than the binding energy of the electron in inner shell, why the photon kick out the electron orbiting in inner shell? It is always easier to kick out the electron with less binding energy, is it not?
  45. S

    Why do we have a saturation current in photoelectric effect?

    I had this question popped into my mind when I was reading this topic one day. In the photoelectric experiment, when light, having frequency greater than the threshold frequency, falls on a metal, electrons are emitted. Since electrons emitted are of different energies (I presume it's because...
  46. 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...
  47. BrianKim

    Photoelectric Effect and Conic section

    Hi. I'm high school student who is doing a math project. Yesterday, my project partner (to be precise, his teacher) told me that one can prove the photoelectric effect with conic section, especially with hyperbola. (But, actually, I can't even understand the meaning of the statement. For me...
  48. D

    Mechanics of the photoelectric effect

    Given an experiment of the photoelectric effect, if we keep the intensity of the shining light source constant, by increasing the frequency of the light, the number of ejected electrons from the metal surface "decreases". I understand that increasing frequency (assuming it is already higher than...
  49. RJLiberator

    Questions Regarding the Photoelectric Effect

    Homework Statement We are performing a lab on the photoelectric effect tomorrow and have some pre-lab questions. 1: If an electron must use an energy equal to the work function of the phototube cathode, in order to escape the cathode's surface, how much kinetic energy does it have once it...
  50. ZapperZ

    "Violating" Einstein's Photoelectric Effect Model - Comments

    ZapperZ submitted a new PF Insights post "Violating" Einstein's Photoelectric Effect Model Continue reading the Original PF Insights Post.
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