All Questions
13
questions
8
votes
2
answers
2k
views
How does a photon "cheat" its way past a neutron?
I learnt here Is a neutron deflected sideways by a laser beam? that a photon beam has no influence on the motion of a free neutron in the first and second approximation. Now I'm interested in what ...
- 10.6k
4
votes
2
answers
587
views
Compton scattering with free electron
When the photon is incident on free electron, we say that compton happens. Though, we require that photon is x-ray or gamma ray. I wonder why at least x-ray is required.
I have my own observation and ...
- 367
1
vote
1
answer
90
views
Assume a photon has a wave function, what can be said about its Hamiltonian and eigenvalues?
I understand a photon does not have an associated wave function, but what if we assumed a photon does in fact have a wave function. How would this look and how could its Hamiltonian be determined?
- 29
0
votes
1
answer
43
views
Does the absorption of ionizing radiation increase the absorber temperature?
Let's say a gamma ray shielding material (assume water) has absorbed 1 joule of gamma ray ionizing radiation, does the absorbed 1 joule eventually end up as heat in this material?
I ask this question ...
- 3,916
4
votes
2
answers
409
views
How does a photon interact with a conduction band electron?
In conductors the valance and conduction band overlap so there are free electrons. If a radio frequency photon hits one of those electrons (as in the case of an antenna), what will that electron do? ...
- 41
1
vote
3
answers
295
views
Is the source of electromagnetic radiation exclusively the excited subatomic particle? [closed]
The treatment of EM radiation without including the topic of photons is successful. Just as the description of thermal processes works without the inclusion of the atomic level. Or the gas theory. But ...
- 10.6k
6
votes
3
answers
703
views
Which particles can be described as an excitation of the electromagnetic field?
In my teacher's class notes, came across this definition of light today:
Light is an excitation of the electromagnetic field, with photons being the lowest energy excitation.
And the way in which it ...
- 548
4
votes
2
answers
395
views
What is the connection between quantum optical photons and particle physics' photons?
There has been quite some debate amongst users with different backgrounds about the usage of the word photon.[1, 2] The most apparent disagreement was on whether a photon has a wavelength. I don't ...
- 3,260
0
votes
1
answer
2k
views
Finding number of photons per second crossing an area with distance $d$ from a radiating point
Let's say I have a radio tower with frequency $v[HZ]$ and power output of $P[W]$ radiating uniformly across all directions, and I need to find the number of photons crossing an area of $1m^2$ per $...
- 151
0
votes
1
answer
213
views
why is cross section of pair production in field of electron smaller than that in the field of nucleus?
Pair production cannot take place in a vaccum since momentum conservation would be violated. However it can take place in the field of a nucleus or an atomic electron. Why, though, is the cross ...
- 119
2
votes
1
answer
3k
views
Why does the cross section for Compton scattered photons decrease with increasing energy of incident photon?
The cross section is independent of energy for energies less than electron's mass, but for greater energies the cross section of compton scattered electrons decreases, why?
- 119
22
votes
5
answers
12k
views
What exactly is meant by the wavelength of a photon?
I've been thinking about this for quite some time, and from looking online I haven't found a satisfying answer.
Lots of photons, such as visible-light photons have very small wavelength (which from ...
- 379
56
votes
3
answers
9k
views
Why doesn't light affect a compass?
In our daily life a lot of photons of visible light, infrared and radio etc move around us. We know that light is an electromagnetic radiation. So why doesn't that electromagnetic radiation affect a ...
- 1,925