Photoelectric effect Definition and 395 Threads

Hi, I'm studying quantum theory now and one thing I couldn't understand is why the frequency (and not the intensity) is the only respon sible for starting the photo eletric effect? I didn't understand this expression E total = E0 + E kinetic E0 = work functio n []'s John

Hi everyone, I've been reading bits about the photoelectric effect, about how when you shine a light on a strip of metal its spits out electrons etc. What do they mean by spits out electrons? Is it that it actually spits the electrons out? If so where do they go? The book I'm reading uses...

Homework Statement http://phet.colorado.edu/simulations/sims.php?sim=Photoelectric_Effect Part 6 1. Set the cathode metal to copper and light intensity to 50 %. 2. Tabulate eight values for frequency and photoelectron energy in Joule. 3. Draw a graph of frequency and...

What determines if the photoelectric effect occurs? There are several aspects on this topic that I don't really understand such as: - What is the relationship between the frequency of the incident photon, threshold frequency and the ejection of electrons? - What is the relationship...

Homework Statement True/False: In the photoelectric effect, the cut-off (threshold) frequency depends on the intensity of incident light. Homework Equations hv = W + 1/2mv^2 v = W/h The Attempt at a Solution The threshold frequency depends on the wavelength of incident light...

What happens to the ions that are released from the material after e- are released? How come the material doesn't completely degrade?

Hi, In a double slit experiment, shooting a photon will produce interference pattern on a screen. Using a detector to detect which slit the photon passed through will destroy the interference pattern. The photon will pass through only 1 slit, and cause slit pattern on the screen. The...

First check out this picture (from the book I'm reading) http://imageshack.us/photo/my-images/838/25090635.png/ It says that the collector's voltage is decreasing , can you explain why? also it says "few photoelectrons can overcome this potential difference", since the potential...

Hi, I am interested to know if photoelectric effect happens in a "single atom" of say Iron which is in a vacum... ? if yes, what is the workfunction of Fe2+ ? If no what is the ionization energy of Fe2+ in eV? Thanks in advance.

Both Compton effect and photoelectric effect involves collision of photon with a electron. I don't understand why one has scattering but one is simply kicking out electron. The photoelectric effect said light can transfer it's energy only in quantized units of h bar, so why the photon in...

OK, so recently I have learned that in the early 20th century, while Max Planck was attempting to explain the quantum nature of light, two men named Philip Lenard and Heinrich Hertz discovered the photoelectric effect. They found that an electron must absorb a specific amount of energy...

Homework Statement A graph displays the kinetic energy of photoelectrons as a function of frequency of light falling on a cathode in a photoelectric cell. If the cathode is replaced with one of greater force of attraction to its electrons, describe how a graph of kinetic energy against...

Hello, This question is based on the passage to the left. Please I need some one to explain it to me in "baby steps" if possible. I already read another explanation of it .. (posted below the picture) but i still can't understand how the final kinetic energy will be the same as the initial...

Homework Statement Em radiation of frequency .88X10^-15 Hz falls upon a surface of work function 2.5 eV. A)Calculate Max KE B) If a nearby electrode is made negative with respect to the first surface using a pd V, what value is required for V if it is to be just sufficient to stop any of...

Homework Statement A photon with an energy of 15.2 eV enters a hydrogen atom in the ground state and ionizes it. With what kinetic energy will the electron be ejected from the atom? Homework Equations Photoelectric Effect equations. The Attempt at a Solution E=W+KE I don't...

Homework Statement If the energy flux associated with a light beam of wavelength 3 x 10-7 is 10 W m-2, estimate how long it would take, classically, for sufficient energy to arrive at a potassium atom of radius 2 x 10-10 in order than an electron be ejected. Homework Equations E_x = h...

First of all, I would like to apologize if this question is in the wrong section of the forums. I'm not sure if the photoelectric effect should go into "Quantum Physics", "Classical Physics" or even "Homework & Coursework Questions" Descriptions of the photoelectric effect commonly states the...

why does photoelectric effect show the corpuscular nature of light? can't we approach photoelectric effect phenomenon by regarding radiation as a wave? can't a wave just give the energy it carries to the electron causing it extracting? another question: with respect to...

1-if we want to increase the number of ejected photo-electrons, can we change the frequency of the electromagnetic radiation? 2-if i calculated the number of the ejected photo-electrons and the kinetic energy of each electron, how could i then calculate the voltage of this photoelectric cell?

Homework Statement Lenard's experiment on photoelectric effect concluded mvm2/2 = eVs where vm is the highest velocity of photo electrons and Vs is the stopping potential. From this he concluded maximum velocity of photo electrons depends only on the wavelength of light used and not on the...

Hello Before a photon hits an electron, the electron originally had a kinetic energy, if f = f0 we know that Kmax = hf -hf0 = zero shouldn't the electron's kinetic energy increase the photon hits it? not the converse?

Homework Statement Hi there. I have two questions and in both I believe that no photoelectrons will be emitted from the surface. Question 1 A metal with a work function of 9 x 10^-19 J is irradiated with UV radiation of wavelength 180 mm. Will photoelectrons be emitted from the...

Hi there, I have this problem with this photoelectric effect experiment. In the image of my attachment particulates will be ejected from C and move to D. The electric field(by A and B) will change the particulates trajectory to A, B or will not change this? Thanks Tony PS: Sorry...

Homework Statement "A blue laser beam is incident on a metallic surface, causing electrons to be ejected from the metal. If the frequency of the laser beam is increased while the intensity of the beam is held fixed, a)the rate of ejected electrons will remain the same but the maximum...

Thought to put this here because of the wave-particle duality ties. My question, that I already asked a tutor was how come electron ionization is due to frequency, and not intensity. He told me that it was because of nature's "no free lunch" policy and that changing the intensity was just...

Homework Statement This has to do with a simple photoelectric effect setup: If there is no current, would increasing the frequency of the light result in at least some current? If there is some current, would increasing the frequency result in a maximum current? Homework Equations...

If the photoelectric effect causes light to knock electrons out of metals, why don't the metal surfaces in our home lose electrons when we turn on the light? I'm a third-year college student. This question was a discussion question in the back of the chapter, and I thought it was a great...

Ok I'm doing some gamma ray spectroscopy and finding that the two main effects occurring are Photoelectric and Compton. I want to fully hash out similarities and differences for these two effects so I know exactly what's going on. As a starting point, I know that in the photoelectric effect the...

Homework Statement During successive illumination of a surface of a particular metal with radiation of wavelengths \lambda _1 =0.35 \mu m and \lambda _2=0.54 \mu m, we find that the respective maximum velocities of the photoelectrons have a difference between each other of a factor 2...

Homework Statement A monochromatic light beam with wavelength \lambda =405 nm and intensity 3 \times 10 ^{-9}\frac{W}{m^2} points to one of the plates of a plane metallic capacitor (photocathode). We apply a difference of potential of 1.15V between the 2 plates in such a way that we slow...

Hey guys, assume that i performed and experiment to measure the maximum kinetic energy of electrons released due to the photoelectric effect due to light falling on a metal target (i.e. Sodium). KE = hf - W (where W = work function, f = frequency and h = Planck constant) since KE = 1/2...

Homework Statement Chlorophyll and the Photoelectric Effect I have been trying to put together a lesson on the photoelectric effect applied to biology and chemistry concepts, and have been unable to find an explanation for some things. Here is some background: When chlorophyll is...

1. The problem statement A hydrogen atom has an electron in the fundamental state. a. Show that a radiation with λ = 50 nm will ionize the atom. b. What will be the excess kinetic energy of the electron in joules? What is this question asking? Is it asking what wavelength will free...

i know that einstein explained it in terms of particles but can maxwells EM waves explain the photoelectric effect aswell?

Homework Statement "The threshold frequency of a particular metal surface is 5.6 × 1014 Hz. Calculate the maximum kinetic energy of emitted electrons if the frequency of the light striking the metal surface is double the threshold frequency." Taken from AQA Physics Exam 2009 Homework...

It puzzles me. In Einstein's paper on the photoelectric effect he proposed that photons with E = nhf were the explanation. Wouldn't a more elegant explanation be that the tangent of the electromagentic wave must take on discrete values because of the boundary conditions between the emitter...

This is more of a conceptual question. Homework Statement -------------------- 1.KE_{Max} = hf-\phi 2.\phi = Work Function. The minimum energy required to free an electron with a photon 3.E=hf This it the energy of a photon --------------------- In my book it says that" hf > \phi"...

Homework Statement In a photoelectric-effect experiment, light of wavelength (x) nm is incident on a sample of sodium. The work function of sodium is (y) J. Calculate the stopping potential required to just stop all electrons from reaching the anode. Homework Equations To work out...

HELP! photoelectric effect Ok guys got a question on quantum physics - photoelectric effect i want to run past you before i attempt a solution. The question is as follows; In a photoelectric-effect experiment, light of wavelength 420nm is incident on a sample of sodium. The work function...

Homework Statement Which of the following statements about the photoelectric effect are true? -(T/F) The number of emitted electrons depends on the frequency, not the number of photons. -(T/F) The radiation needs a minimum number of photons for any electrons to be released. -(T/F) The...

Ok guys got a question on quantum physics - photoelectric effect i want to run past you before i attempt a solution. The question is as follows; In a photoelectric-effect experiment, light of wavelength 420nm is incident on a sample of sodium. The work function of sodium is 3.67*10-19 J...

Homework Statement What potential difference must be applied to stop the fastest photoelectrons by a nickel surface under the action of ultraviolet light of wavelength 220 nm? work function of nickel is 5.00eV.Homework Equations h[c]/[\lambda] = \Phi + eVThe Attempt at a Solution h=6.6x10^-34...

The theory I have read When you charge an electroscope with a negatively charged rod, electrons are repelled to the bottom of the electroscope and the gold leaf rises. Then when you shine light above the fundamental frequency on the top plate of the electroscope, electrons are liberated from...

Hi there, Im having a problem with the results I am getting for an experiment I am doing in relation to the photoelectric effect. My graph is very similar to that in the attachment, except for the fact that the line at A and again after the drop is sloping at a very steep angle to begin...

Homework Statement The question asks me to prove that the photoelectric effect cannot occur with a free electron. ie. one not bound to an atom. A hint is also provided: Consider the reference frame in which the total momentum of the electron and incident photon are zero. Homework...

Hey all, can anyone answer this question?? according t einstein's theory on photoelectric effect if the photon's energy is less then the work function of the material, electron can not come out... My question is: what happens when a lower energy(less then work function of a material)...

I wonder why the thread on Lamb's paper was locked? I was hoping to take part in the discussion.

Lamb and "The Photoelectric Effect Without Photons" I've recently been pointed by two different people to this paper by Lamb (yes, that Lamb) and Scully: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680009569_1968009569.pdf . The title is "The Photoelectric Effect Without Photons."...

Homework Statement The work function of chromium metal is 7.2 x 10-19 J. What is the maximum speed an electron can be moving if it is ejected from chromium metal by light of wavelength 250 nm? (Answer: u= 4 x105 m/s) Homework Equations \Phi = h v_{0} KE = h v_{light} - \Phi =...

Hi When a photon of insufficient energy (lower that the metal's work function) arrive on the metal's surface, what will happen? One part of my notes says that it will be "reflected with no loss of energy", but my teacher has recently stated that it will be absorbed and emitted back as...