All Questions
7
questions
2
votes
2
answers
348
views
If all matter can emit at all wavelengths, can all matter absorb at all wavelengths too?
Based on Planck’s law all matter can emit at all wavelengths at different intensities dependent of temperature. I was wondering if this holds true, does all matter absorb all wavelengths too, at ...
- 647
1
vote
1
answer
101
views
Trouble with Einstein coefficients - what is the meaning of the transition probability?
Perhaps it seems to be a not very intelligent question, but I am unfortunately not able to understand what the probability per second that a molecule will absorb a photon is, as part of the theory of ...
- 103
3
votes
0
answers
580
views
What is the relationship between emissivity $\varepsilon$ and the imaginary part of relative permittivity constant $\epsilon^{''}_{\rm r}$ if any?
In terms of the Stefan-Boltzmann law a body that does not absorb all incident radiation emits less total energy than a black body and is characterized by an emissivity $0<\varepsilon <1$ such ...
- 703
2
votes
2
answers
624
views
Can inner electrons get excited? Can an already excited electron get excited again without first dropping to a lower energy level?
Is it only the valence electrons that can get excited or can the inner electrons get excited too?
Plus, say for example can a electron of a hydrogen atom go from n=2 to n=3 without first returning to ...
- 77
3
votes
1
answer
5k
views
What is the difference between scattering and absorption/emission?
As far as I know, scattering occurs when light excites the atoms or molecules to their higher energy state(virtual state for scattering) followed by emitting photons corresponding to energy ...
- 49
4
votes
1
answer
178
views
How do we detect infinitely narrow emission / absorption lines within continuous electromagnetic spectra?
This always bothered me, especially in the case of absorption lines. for instance, if you have a blackbody emitting a continuous spectrum, and then a filter in front that only filters out one very ...
- 41
15
votes
3
answers
2k
views
Why don't absorption and emission lines cancel out in our Sun?
I was looking at this answer on why absorption lines and emission lines don't cancel out:
An experiment shining light on the material and looking at the
reflected spectrum will see absorption ...
- 2,005