All Questions
24
questions
-4
votes
0
answers
23
views
Is there an IR-camera-detectible color that can be the coat for a material to transfer the material heat by emitting into the space? [closed]
If we see a material it is coloured in a color that our brain could easly recognize. But when we look at it by the help of an IR camera it could also be coloured and if two materials have same ...
1
vote
3
answers
171
views
How to Measure Energy of a Electromagnetic Wave accounting also for frequency?
We know a way of measuring energy of a electromagnetic wave is the Poynting vector, which is independent of the frequency. But let's say we want to make two different electromagnetic waves, with ...
0
votes
1
answer
119
views
Why is energy not conserved instantaneously in electromagnetic waves? [duplicate]
I don't know if its a valid question but it's been bugging me for a while so I'll ask it.
I know that the Poynting Vector $\vec{S}$ gives the intensity of the electromagnetic wave, and its related to ...
- 1,638
1
vote
0
answers
16
views
Does a standing wave on a path have different free energy than a traveling wave?
My somewhat naïve view is that the standing wave is "bound" to its path, and thus higher in free energy than a traveling wave of equivalent amplitude and wavelength. But I'm not sure how ...
- 57
2
votes
1
answer
178
views
Time delay between consecutive photon absorptions by atoms/molecules?
We are just getting introduced to some basics of quantum physics at school and in my nationally prescribed school book, its written that:
Planck assumed that radiation could be subdivided into ...
- 1,168
1
vote
3
answers
2k
views
Energy transfer with electromagnetic waves
As we know that the electrical energy is transferred via electromagnetic waves from the source to the load. My question is that, even if there is transfer of energy through the electromagnetic waves, ...
- 962
0
votes
2
answers
87
views
Why is there more energy in a gamma wave vs. lower frequencies?
If energy is a function of frequency and amplitude, why are microwaves and lower frequency waves considered “less energetic” than gamma waves only as a function of their frequency and wavelength?
0
votes
0
answers
34
views
How do you calculate intensity given the energy of a wave?
I’m a bit confused when it comes to calculating intensity versus energy of a wave.
If I’m given a wave with an energy of 1 eV, how do I calculate its intensity ? I know intensity is usually measured ...
- 101
5
votes
5
answers
2k
views
Why the energy of electromagnetic waves is directly proportional to frequency whilst for mechanical waves this is not true?
The energy of a photon is directly proportional to its (angular) frequency:
$$
E=\hbar \omega.
$$
The energy of a classical mechanical wave is, however, proportional to the square of $\omega$:
$$
E=\...
- 1,335
0
votes
1
answer
65
views
Is the energy of an electromagnetic wave, in electron volts, an 'average' or a 'peak' value?
Since EM waves oscillate, is the energy given in eV an average or maximum value?
In a related question, can a detector (of whatever sort) 'miss' an EM wave if the amplitude is at a minimum when it ...
- 4,509
2
votes
4
answers
67
views
How come you see what happens to the energy of a system when 2 free linear plane waves cancel out?
Suppose we have 2 waves which perfectly cancel each other out, say, same frequency $f$ but with different phase (the second one has a difference of $\pm\pi$). Energies for both waves are the same $E=...
- 382
0
votes
1
answer
77
views
How an EM wave holds energy?
Imagine a lone charged particle. It emits an EM field which propagates outwards at the speed of light. But since there is no other charged particle to interact with, there is no repulsion or atraction,...
- 2,982
2
votes
1
answer
70
views
Is my understanding of thermal energy correct?
When I think of thermal energy I have always imagined that it some "wave" radiating off molecules (like light) but now it seems like heat is not radiating off molecules at all. Heres my understanding:
...
- 21
4
votes
2
answers
175
views
Can wifi signal reception be improved by opening a door? [closed]
Use Case
A wifi user is in a different room than the router. The computer is having a hard time connecting and receiving the wifi signal.
Engineering Question
Can the wifi signal from the router to ...
- 141
4
votes
1
answer
1k
views
Refraction: Energy flow, tunneling and Evanescent EM waves
In the full internal reflection case where we have a refracted evanescent wave, If another object is nearby, then we could have wave tunneling phenomenon(frustrated total internal reflection). I am ...
- 7,720