Tagged Questions
1
vote
1answer
45 views
Is the de Broglie wavelength of a photon equal to the EM wavelength of the radiation?
Is the de Broglie (matter) wavelength $\lambda=\frac{h}{p}$ of a photon equal to the electromagnetic wavelength of the radiation?
I guess yes, but how come that photons have both a matter wave and an ...
2
votes
1answer
74 views
Holograms? Sci Fi or future fact?
Based on how light behaves when it passes through mediums, i.e. the wavelength of light changes when it passes through mediums of different refractive indexes, wouldn't it be possible to convert ...
5
votes
2answers
186 views
If photons move linearly, what's actually stopping them from passing through a microwave oven mesh?
So, my understanding is that the wavelength of a photon is the distance traveled in the time it takes it's magnetic field to oscillate. And it's inversely proportional to it's energy and it's ...
2
votes
3answers
195 views
Why aren't the graphs for black body radiation straight lines?
We know that a wave which has greater frequency will have low wavelength and high energy. So, by decreasing the wavelength, the frequency and consequently energy (intensity) of that wave will increase ...
6
votes
2answers
2k views
Why is Near Field Communication (NFC) range limited to about 20cm?
Near Field Communication (NFC) operates at 13.56 MHz.
Near Field is the region situated at a distance r << λ
λ = c/f
...
3
votes
3answers
159 views
What if $\gamma$-rays in Electron microscope?
I was referring Electron microscopes and read that the electrons have wavelength way less than that of visible light. But, the question I can't find an answer was that, If gamma radiation has the ...
2
votes
2answers
396 views
Is all kind of light same speed?
Is there any speed different between blue or red color? Is there speed different? or there are same speed?
3
votes
2answers
1k views
In electromagnetic radiation, how do electrons actually “move”?
I've always pictured EM radiation as a wave, in common drawings of radiation you would see it as a wave beam and that had clouded my understanding recently.
Illustration on the simplest level:
...
4
votes
2answers
12k views
Why does wavelength change as light enters a different medium?
When light waves enter a medium of higher refractive index than the previous, why is it that:
Its wavelength decreases?
The frequency of it has to stay the same?
2
votes
3answers
936 views
Some questions about car radio and cellphone antennas
1-Why the antenna of the radio of cars is located outside the car and not inside?
2-If the answer to 1 is because that cars are like Faraday cages then how come my cell phone can receive signal ...
6
votes
3answers
790 views
Why is it necessary for an object to have a bigger size than the wavelength of light in order for us to see it?
I keep hearing this rule that an object must have a bigger size than the wavelength of light in order for us to see it, and though I don't have any professional relationship with physics, I want to ...
5
votes
2answers
541 views
What is the minimum wavelength of electromangetic radiation?
As a first approximation, I don't see how a wavelength of less than 2 Planck distances could exist. The question is: are there any other limits that would come into play before that?
For example:
...
3
votes
1answer
183 views
Is the number of wavelengths of light spanning a distance invarient with respect to spacetime distortion?
I was recently asked by a friend how the expansion of spacetime effects photons. I gave him what I feel is a satisfactory general response, but it got me wondering how, exactly to calculate this ...
0
votes
1answer
127 views
Merge different wavelength rays
Let's say an array of rays of light is given.
Each ray has a specific wavelength (in the range of visible light).
Example:
...
4
votes
4answers
1k views
Light emitted by an object according to its temperature
According to this picture
the light emitted by an object depends on its temperature.
That makes perfect sense when we heat a metal. As its temperature raises we see it red at first, then orange, ...
3
votes
2answers
317 views
Magnetron limits
What are the practical limits on generated wavelength in a Magnetron?
We know that Magnetrons could be used efficiently for generating microwaves for water heating, or for radar applications, but ...
9
votes
4answers
783 views
What causes polarised materials to change colour under stress?
Our physics teacher showed the class a really interesting demonstration. He used two polarised filters in opposite orientations, then he took some antistatic tape and stretched it under the two ...
