- #1
- 346
- 1
Why can't photons be the same as energy? How are they different?
Regarding Heisenberg's question, it's still unknown what would happen if photons had no energy left to transfer.
- #2
Danger
Gold Member
- 9,765
- 253
Welcome to PF, BW.
Photons are the bosuns (carrier particles) for electromagnetic energy. While they are not energy themselves, they do transport it from place to place.
That's the best that I can do by way of explanation, given my own limited education, but others will be along shortly who can do a better job of it.
Photons are the bosuns (carrier particles) for electromagnetic energy. While they are not energy themselves, they do transport it from place to place.
That's the best that I can do by way of explanation, given my own limited education, but others will be along shortly who can do a better job of it.
- #3
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
- 9,625
- 8
Energy is a property of a particle/system. Saying photons are energy is like saying electrons are charge.Bright Wang said:
- #4
- 267
- 2
Very well put, easily understood descriptions!
I love it when longwinded dogma is avoided on subjects like this.
(to help prevent 'longwinded' responses to my response, I replaced "definitions" with descriptions. lol)
I love it when longwinded dogma is avoided on subjects like this.
(to help prevent 'longwinded' responses to my response, I replaced "definitions" with descriptions. lol)
- #5
- 551
- 3
Another good way to put it would be to say that photons have properties other than their energy. In fact, photons also carry momentum and angular momentum.
- #6
- 14
- 0
Is it possible to have a photon with no energy left to tranfer?
Would it behave differently?
Would it behave differently?
- #7
rcgldr
Homework Helper
- 8,844
- 621
If photons have momentum, when an electron captures a photon, does it make any difference in the electrons energy or path after capture depending on the direction the photon was traveling before it was captured by the electron?
- #8
- 379
- 0
Jeff Reid said:
A man called Heisenberg asked that around a century earlier. He was never certain as to what would happen
.- #9
rcgldr
Homework Helper
- 8,844
- 621
Jeff Reid said:
dst said:
If it's unknown, then why do so many people state that photons have momentum? Is there any other way that photons could exhibit momentum properties?
- #10
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
- 9,625
- 8
In the analysis of Compton Scattering, the photon is assumed to be a particle that has a momentum determined by the de Broglie hypothesis.Jeff Reid said:
- #11
Dale
Mentor
- 34,823
- 12,879
Yes. Energy and momentum are conserved.Jeff Reid said:
- #12
- 5,432
- 291
When an atom absorbs or emits a photon, momentum is interchanged. This was first explicitly shown by Einstein in a 1916 paper.
He shows that when matter and radiation interact, the momentum interchange is necessary to get the Planck radiation curve.
He shows that when matter and radiation interact, the momentum interchange is necessary to get the Planck radiation curve.
- #13
rcgldr
Homework Helper
- 8,844
- 621
OK, but don't electrons have discreet energy states? So if an electron captures a photo, and jumps up to the next energy state, regardless of the direction of the photon, where does the momentum change due to the direction of the photon go?
On a related issue, what determines if a photon will be captured and released as if reflected (mirror mode) as opposed to released with the same phase and direction (laser mode)?
On a related issue, what determines if a photon will be captured and released as if reflected (mirror mode) as opposed to released with the same phase and direction (laser mode)?
- #14
Dale
Mentor
- 34,823
- 12,879
Electrons only have discrete energy states when they are in atomic orbitals. In that case the momentum "goes" into the whole atom.
- #15
- 5,432
- 291
It is as DaleSpam says. This is the process by which atoms can be cooled by a carefully tuned laser 'molasses' beam.
The beam is tuned to just below the frequency of an absorption line, so only atoms moving towards the source of the beam will absorb, and therefore slow down. The re-emisson of the photon is random, and the overall effect is to slow down the atoms.
The beam is tuned to just below the frequency of an absorption line, so only atoms moving towards the source of the beam will absorb, and therefore slow down. The re-emisson of the photon is random, and the overall effect is to slow down the atoms.
- #16
- 291
- 0
dst said:A man called Heisenberg asked that around a century earlier. He was never certain as to what would happen
Ha ha! kudos on this one dst
1. What is a photon and how is it different from energy?
A photon is a fundamental particle of light, while energy is a measure of the ability to do work. A photon is a form of energy, but energy can take many different forms such as thermal, electrical, or nuclear.
2. Can a photon exist without energy?
No, a photon is a form of energy and cannot exist without energy. All photons carry a specific amount of energy, which is determined by their wavelength or frequency.
3. How do photons and energy interact with matter?
Photons and energy can both interact with matter through the process of absorption and emission. When a photon or energy particle interacts with an atom, it can cause an electron to move to a higher energy level or be released, resulting in a change in the energy of the atom.
4. Which one is more important in everyday life, photons or energy?
In everyday life, both photons and energy are equally important. Photons are responsible for creating light, which is essential for our vision and many technological applications. Energy, on the other hand, is necessary for all forms of life and is used in various ways in our daily activities.
5. Can photons and energy be converted into each other?
Yes, photons and energy can be converted into each other through the process of pair production and annihilation. In pair production, a photon is converted into an electron and a positron, which are both forms of energy. In annihilation, an electron and positron collide, resulting in the creation of photons.