Photon Definition and 1000 Threads

I don't know where I'm going wrong with this problem - I was so sure I had it right but the online grader tells me otherwise :oldfrown: Homework Statement An electron in a one-dimensional box has ground-state energy 2.60 eV. What is the wavelength of the photon absorbed when the electron...

Hi everyone, Anybody knows if the photon energy (frequency * Planck's constant) can be derived from more basic physical principles or this formula was "invented" to explain the photo-electric effect or black body radiation? If you know a way to derive it, please share. Thanks a lot !

Hi, so Newton said that gravity was like or equivalent to a force? When I learned about SR we were talking about the passing of time as defined by a photon bouncing between two parallel mirrors. So when we're sitting our two parallel mirrors in a gravitational field, even though I suppose...

I was wondering while doing some work on the photoelectric effect about how it is that photons interact with their environment. The question that I have is why or how does a massless particle such as a photon reflect of a surface such as a mirror. My first thoughts went to collisions with the...

Homework Statement I want to calculate/estimate the average photon energy from a galaxy cluster incident on the mirror of a X ray telescope (Chandra to be specific) . The cluster has redshift z and at constant uniform temperature T Homework Equations Specific Intensity of thermal...

Homework Statement Show that the scatter angles of the photon (θ) and electron (Φ) in the Compton effect are related by the relation: ##cot (θ/2 )=(1+\frac{hf}{mοC^2}) tan(Φ) ## Where f is the frequency of incident photon 2. The attempt at a solution I wrote down the equations of conservation...

Can an electron absorb a photon and jump to a higher orbit if the next level is already full of electrons? please explain what happens and also link info that might help me with electron/ photon interaction. I have many questions. Thanks

Homework Statement a) An electron is trapped in a one-dimensional box that is 526 nm wide. Initially, it is in the n=2 energy level, but after a photon is absorbed the electron is in the n=7 energy level. What is the wavelength of absorbed photon? b) Eventually, the electron ends up in the...

Homework Statement A 100W sodium lamp(lambda=589nm) radiates energy uniformly in all directions. (A) At what distance from the lamp will a totally absorbing screen absorb photons at the rate of 1.00 photon/cm2.s? (B) What is the photon flux on a small screen 2m from the lamp? Homework...

I'm trying to understand how the Z and the \gamma are interpreted as combinations of the and B gauge fields. I'm comfortable with where the W_{1}, W_{2}, W_{3} and B come from, and I get that the W_{3} and B get related to the Z and the \gamma by the 2x2 matrix containing the weak mixing angle...

The green dots represent photons in an anti-bunched state, squeezed light. The red dots represent photons in a semi-bunched state, laser light The blue dots represent photons in a bunched state, thermal light The complex setups used in entanglement experiments only squeeze light in amplitude...

Homework Statement A distant observer is at rest relative to a spherical mass and at a distance where the effects of gravity are negligible. The distant observer sends a photon radially towards the mass. At the distant observer, the photon's frequency is f. What is the momentum relative to...

My Quantum Field Theory notes, after explaining the Lorentz condition, say this: I have some questions about this. 1) What exactly does the polarization of a photon mean? 2) Why do the degrees of freedom of the potentials determine the polarizations of the photon? 3) If instead of the Lorentz...

Hi there, If a photon wavelength (yellow) is isolated from the other wavelengths that sunlight emits (once it gets to earth), can that particular particle/photon be distorted slightly into a wavelength that is shorter (perceived as green)? If yes; please explain. If no; please explain. Thank...

Is it possible to produce an entangled photon pair and be able to delay the reception times by introducing something like a fiber bragg grating which has multiple indices of refraction which propagate wavelengths at different frequencies? Or will, because of their entangled state, do some...

How is the photon torpedo supposed to work?

Why helicity of phon is 1 but not 3 or higher?Is there any quantity relation between the circular polarization of light and spin of photon?Why spin of graviton is 2?Is there any relation with vector and tensor charater of electromagnetic and gravitation fields and of P symmetry?Why do the...

why light can't penetrate the prism with 45 degree angle?

Consider a measurement of a photon after it has passed a polarisationfilter. Does the photon jump in a (polarisation-)eigenstate by passing the filter? Does the filter do a measurement? Is the filter part of the entire measurement?

Homework Statement Photon of energy E=0,3MeV is scattering at an angle \phi=\frac{2\pi}{3}. Calculate the energy E' of scattered photon and emitted electron. Homework Equations -Compton effect The Attempt at a Solution By Compton effect...

If I shot a 5khz photon at a theoretical antenna made of one copper atom, the electron would absorb the photon and gain energy. What is it about that boost in energy that makes the electron oscillate at 5khz in the direction perpendicular to the photon's direction of propagation?

Let's say you have 2 100% efficient reflective surfaces exactly parallel to each other. If you theoretically managed to place photons at exactly 90° angle of incidence. So this beam of visible light (and I want to stress that) is going to stay there as long as there is no interaction, the beam...

Hello, I have read some of the posts which discuss the meaning and mistakes involving the equation: ## m_0 = \frac{h f }{c^2}.## My question has to do with gravitation. I would like to know if it is correct to associate to a photon with frequency f, crossing a region near a mass M, a...

Matter has a wavefunction associated to it. But what about light? Does it have both a electromagnetic wave described by Maxwell's equation and a wavefunction described by Schroedinger's equation? Or is the electromagnetic wave considered to be the wavefunction of the photon? I read somewhere...

I would like to ask a quick (I suppose) question. Does a photon have definite energy in Heisenberg picture? My motivation for this question comes from reading that Hamitonian is generator of time evolution. But in Heisenberg picture time evolution is associated with operator not quantum system...

Homework Statement It's in attachment Homework Equations E=hf. Where h= planks constant and f= frequency The Attempt at a Solution I know that the flux of a photon is (# of photons)/(sec m^2) I don't know the number of photos but I do know the frequency and power. E=(6.6261*10^(-34)) J•s *...

I red that photon has wave properties so it can go through both slits simultaneously in the double slit experimen. What about photons that hit our eyes and construct our vision? How do we know which path they traveled and what they reflected, or to say it better how would you describe the...

Hi. Charge is one of the few properties a black hole can have. EM interaction is mediated by photons. How can they escape the BH?

In my undergraduate days I remember learning about the double slit experiment etc. in quantum mechanics. And I'm only now starting to learn about the Standard model. So there are these fields; higgs, electro-magnetic, strong and weak nuclear. So if a photon is a perturbation in the...

Here is my answer. Add any clarifications you might have.. Since the photon is a wave, the answer is similar to the answer to the question, "What is the size of a wave?" The size of a photon depends on how precisely you know the photon's momentum, or equivalently, by deBroglie's relations, how...

Hello PF members, In Newtonian perspective, applying a force to a object like ball causes it starts to moving and getting more speed and more energy. Do photon apply a force to the electron when it interacts with the atom and electron absorbs it? It seems electron gets more energy and goes to...

Homework Statement Compute the radiation pressure exerted by a gas of photons (according to kinetic theory). There are N photons, each with energy hf, the momentum is hf/c, and the walls are perfectly reflecting. Express the pressure in terms of N, V, and the product hf. Homework Equations...

Probably a simple question, but I'm honestly at a loss here. It is well known from the photoelectric effect that an electron will accept only a specific amount of energy (quantified energy) from a photon, otherwise it will not accept it. What happens with the photon that collides with an...

Homework Statement A photon with energy E collides with stationary mass m. They form a single particle together, what is this new particle's mass and what is its speed? Homework Equations Energy-momentum 4-vector P=(E, px, py, pz) Possibly P2=m2 The Attempt at a Solution Using 4- momenta, the...

Hi. Now that I understand the conservation law of angular momentum, and given the fact that c is constant, I infer that if a photon were to go into orbit around a black hole, it could only take a circular orbit. No elliptical orbits for photons, because if it were to follow an elliptical orbit...

A Youtube channel has just uploaded a video proposing a challenge. The question is pretty simple. It can be summed up to: A clock is moving towards you at 50% the speed of light, and eventually it passes you and continues its travel. When the clock is moving towards you, will it appear to tick...

Hello, I have a question: let's assume that some photons are passing ~10m pupil, like in largest telescopes. Are they EXACTLY identical AFTER passing, than before? Or is there some lost of infromation becouse most part of their wavefront is cutted off and we only register ~10m part of it (from...

Homework Statement Doing some past papers but I got stuck to this question! Any medical physicists can give me a hand please? A patient is treated with a 6MVphoton beam, 12.5 x 12.5cm at 110cm (Source to Axis Distance: SAD) to a 9cm depth. The machine is calibrated to deliver 1.0cGy per MU at...

Must single photon be monochromatic or not must?What is coherence state?(in general and in optics),Does a quantum of field have ''single'' frequence(''monochromatic'') or multi-frequence?I know that because quantum mechanics particle ''lies'' in wave packet,so it has multi-frequence due to...

Transition of an electron from the valence to conduction bands (direct transition at a k-point near the band edge) would change the momentum of electron because the sign of the group velocity in valence and conduction bands are opposite. Could one infer that the direction of radiation is a...

Something that recently caught my attention was the slowing of light particles - and keeping them slow. Light naturally slows when passing through transparent mediums, it is only in a vacuum that light move at it's true speed. By passing light through a mask made of transparent liquid crystals...

Hello everyone, I know that the photon has zero rest mass and I know that otherwise the relativistic mass formula would not make sense. When I searched for an answer to the question "how can a particle have zero mass and still possesses energy if E=mc^2" I got an answer saying the mass energy...

What causes the photon to move at different frequencies? Thanks in advance

Does molecular mass increase due to angular momentum (h_bar) received from photon since now we have objects rotating inside the molecule?

What is the most accurate way to think of a photon moving through space? 1) Should we think of it as an entity that travels as an integrated corpuscle that parts the "quark sea" of empty space and maintains it's internal integrity as it moves from point A to point B, or.. 2) Should we think...

[Moderator's note: Spun off from https://www.physicsforums.com/threads/does-the-photon-have-a-4-velocity-in-a-medium.843312/page-2#post-5294258.] The web page http://plato.stanford.edu/entries/quantum-field-theory/ says: "Quantum Field Theory (QFT) is the mathematical and conceptual...

Homework Statement I am NOT a student. Please forgive my asking here, but if you do choose to answer, I would appreciate it. Obviously any or all of the statements below may be incorrect... As I understand it: The more energy a photon has (I know it's also a wave) the greater the frequency...

I searched for, but could not find any name or published value for a constant (with units m-3 K-3) which when multiplied by temperature (in degrees Kelvin) cubed gave the corresponding photon density (in m-3). Does anyone know of such a constant with a published value? I calculated a value, but...

This may be a dumb question, but maybe someone can help me out: Consider a pair of entangled photons A and B, fired at respectively Alice and Bob who both let it go through a polarisation filter at different angles. Now Alice establishes that half of the photons get through her filter, and half...

This may seem an odd question, but I'd really like to find out: is there proof that photons actually exist?