Questions tagged [wavelength]
The wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats, and the inverse of the spatial frequency or wavenumber. Determined by considering the distance between consecutive corresponding points of the same phase, such as crests. Use for wavenumber, wavelength, frequency.
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Mathematical relation between wavelength of wave and area of surface for reflection
I was reading about the reflection of sound waves, and the condition provided is that the reflecting surface's area should be greater than the wave's wavelength. But there isn't a single mention of ...
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Would slowing down a beam of light change its wavelength and frequency?
I confess that I have little knowledge of physics, so this kind of thing really often goes over my head. However, I did read somewhere that the speed of a beam of light is the product of its ...
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Path differences in relation to phase difference
If we had two generators producing waves, say $S$ and $T$, and the waves from $S$ were in phase with the waves from $T$, we know that at some point $P$, if the path difference is $n$$\lambda$, they ...
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Why does Rayleigh-Jeans law agree with Planck's at long wavelengths?
Why does Rayleigh-Jeans law agree with the Plancks distribution at high wavelengths? I know mathematically, that at higher wavelengths, we can approximate the exponential in the denominator by $1+ \...
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In inelastic scattering between photons and electrons, how does light only partially transfer energy?
In the case of elastic scattering or absorption between photons and electrons, the incident light is either fully reflected or fully absorbed and hence it either retains its wavelength or ceases to ...
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Deduce simple formula of collisional broadening for $\Delta \lambda$
The German Wiki states that the broadened wavelength can be given by:
$$\Delta \lambda \approx \dfrac{\lambda^2}{\pi\,c\,\Delta t}$$
with $\Delta t$ as mean collision time given by $\Delta t = l/v$
...
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Wavelength in Multiple Lossy Layers
I would like to derive an equation for the wavelength of a plane electromagnetic wave (normal incidence) in each layer of a multilayered lossy medium, as shown below.
Which equations are required for ...
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How to create a standing wave that doesn't oscillate with the fundamental frequency?
Is there a way to make the string on my violin vibrate in an overtone frequency instead of the fundamental frequency?
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Can we use a different type of wave instead of light to see elementary particles?
I heard that the visible light rays are too "big" to "hit" the elementary particles (quarks, neutrinos etc) so that they can be reflected. So my question is, would we ...
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Very confused about pulse-echo measurements
Heres a link to the question im referring to just in case the image is not visible in the post - https://ibb.co/2vsZy90
Can someone please this mark scheme answer in simple terms. Firstly, what ...
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Energy level photon spectra for different atoms
I'm trying to determine the photon emission wavelength ranges for different atoms.
For hydrogen, it's super simple. We use the $$ E_n = -\frac{13.6}{n^2} $$
Then, if we want to see the wavelength of ...
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What are the underlying concepts of the wavelength? [closed]
For all light waves:
$f = c / \lambda$, where $f$ is the frequency, $\lambda$ is the wavelength, and $c$ is the speed of light.
What are the underlying concepts of the wavelength?
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Tension in a violin string
Say we have a string of fixed size on a violin. If I were to play it open (without pressing down on it) it would vibrate at a certain frequency. If I were to play it whilst pressing down on the middle,...
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Max Planck - what does 'per wavelength' mean?
Planck says
$$B_\nu(T)=\frac{2hc^2}{λ^5}\,\frac{1}{\mathrm{e}^{hc/λk_BT}-1}.$$
It's defined as energy emitted per unit volume per wavelength. I'm not sure if this includes per solid angle, but I ...
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Max Planck - what's the $B$?
Planck says
$$B_\nu(T)=\frac{2\nu^2}{c^2}\,\frac{h\nu}{\mathrm{e}^{h\nu/k_BT}-1}.$$
It is power emitted per unit area per unit angle per unit frequency. This is what I'm curious now.
Let's say we ...
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What is the longest detectable EM wavelength?
What is the longest detectable (by today's technology) EM wavelength? and is there a limit of the energy that those with longer wavelengths that we cannot detect can carry? can there be a galactic or &...
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Difference between white and yellow light bulbs
Whats the difference between the white light bulbs and yellowish tinted light bulbs what makes the color yellowish? Do they both emit multiple wavelengths of all the colors or does one of them emit ...
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Maximum or Minimum energy for transition from $n=2$ to $n=1$ or vice versa?
I know the maximum wavelength line in the Lyman Series in a Hydrogen atom is $n=2$ as transition from $n=2$ (1st excited state) to $n=1$ (ground state) gives the longest wavelength as per the formula $...
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Wave-packet in configuration space and deriving Schrodinger equation with this approach
In the book "Group theory and it's Applications to the Quantum Mechanics of atomic spectra " by Eugene P. Wigner
in chapter 4 The elements of quantum mechanics it is written
Consider a many ...
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Why can’t we see atoms in an optical microscope?
I know, the answer to this question may seem obvious: The resolution/magnification of an optical microscope is limited by the minimum wavelength one uses. This is due to the diffraction limit.
However,...
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Confusion regarding wavelength of stationary waves
Imagine, we have an air column and the the temperature of the air was the same outside and inside the column. If sound waves from a tuning fork then enters the air column, the speed of the standing ...
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Why is first line of Lyman series considered largest ultraviolet wavelength in hydrogen spectrum
I was reading a book which contains a numerical question about largest wavelength of hydrogen spectrum in ultraviolet region. In the solution, it mentions the largest wavelength in ultraviolet region ...
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Confused regarding the wavelength of standing waves and their relation with wave speed
Suppose we have an air column closed at one end and open at one end. We know, the general formula for the wavelength of the stationary waves of different harmonics will be equal to $4L/n$. My ...
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Light in glass/water
When light enters water, the light changes their direction because they only use 75% of their speed in water, because the interactions with the electrons, the wavelength of the photon changes. We SEE ...
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Finding mass of photon with de Broglie wavelength
The de Broglie wavelength equation is given by:
$$\lambda = \frac{h}{mv}$$
Even though this is used to find the wavelength of the matter (matter waves) , I was curious to find the mass of photon ...
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De Broglie wavelength of a photon
The de Broglie wavelength of a photon and the wavelength of its corresponding electromagnetic wave are numerically the same. Is this just a coincidence and the two waves are different or is the de ...
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Does colour of light depend on intensity of light? [closed]
By intensity I mean frequency of light
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If the particle moves with group wave, what $\lambda$ in De Broglie equation should we use?
according to De Broglie equation
\begin{gather} p=\frac{h}{\lambda} \end{gather}
and knowing also that a particle moves with the group velocity not the phase velocity, indicates that has a range of $\...
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Why don't we get infinite energy from a continous emission spectrum?
If the spectrum emitted contains all kinds of photons of all kinds of wavelengths, doesn't that mean it should have infinite number of photons of very small energies? For example, 4000 angstrom to ...
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Is a photon a single wavelength of monochromatic light?
I am confused about all these different interpretations of what a photon is?
I am looking for a simple and practical interpretation.
Therefore, I am asking herein if a single photon corresponds to a ...
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Why the blackbody's spectral emittance isn't a growing exponential in the wavelength?
I have read multiple paragraphs about why we do get the bell shaped curve and the tale goes like this, oscillators with high frequency aren't paying the bell getting excited as they would require ...
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What does "the range of reciprocal wavelengths" mean for a wave packet? (QM)
I'm learning about the derivation of the uncertainty principle via the addition of a finite number of sinusoidal waves of varying wavelengths and frequencies (basically, baby steps towards a Fourier ...
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Relationship between wavelength and storage
I have a question regarding the working of optical discs. We know that Blu-ray disc stores more data than DVD. There are two reasons for that:
The pits are smaller
The wavelength of blue light is ...
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Does the wavelength of a sound change from one medium to another?
In my book, it is written that:
v = fλ in a given medium under conditions of fixed temperature and
humidity.
It is also written that:
one of the more important properties of sound is that its speed ...
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Why does a microwave's faraday cage block microwaves but not larger wavelength radiowaves?
I read that the Faraday cage on a microwave door prevents the microwave radiation from escaping the microwave because the wavelength of the microwaves is "too large to fit" through the holes ...
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Wavelength and propagation constant relation [closed]
Theory
Propagation constant is equal to: $\gamma = j k_z = \alpha + j \beta$
Wavelength: $\lambda = \frac{2 \pi}{Im\{ \gamma \}}$
Wave impedance:
$Z_{TEM} = \frac{\gamma }{ j \omega \epsilon } = \...
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How do you calculate light attenuation by wavelength at a given air mass coefficient?
I am trying to get a good view of light wavelength distribution as a function of viewing angle, with a specific interest as $z \approx 90^\circ$ near the horizon (sunrise/sunset). Air mass ...
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Feynman's QED 36000 revolutions per inch
In Feynman's book, QED, on page 27 he says "As long as the photon moves, the stopwatch hand turns (about 36,000 times per inch for red light); when the photon ends up at the photomultiplier, we ...
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What is the term for the number of wavelengths in a wave packet?
If I have several wave packets, such that they consist of 1, 2, 3, etc. wavelengths of a single wave with a set frequency/amplitude what do the wave packets vary by?
Ie. what is the generic term for ...
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How is it possible that the wavelength of a wave can change but the frequency remains the same? [duplicate]
When let's say a beam of light passes through a transparent glass surface, how is the wave able to maintain the same frequency but the wavelength changes ?
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Can we stop light in a lithium niobate crystal and then recover it later?
Lithium niobate is a peculiar and important crystal, with piezoelectric, optical-electric, and photorefractive qualities giving it many applications due to these properties. It is transparent to ...
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Can a photon have a radius?
I have seen someone answering this question by saying that a photon can has a radius as big as its wavelength, is that true? If it is true Does this then mean a photon of the radio radiation, for ...
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Wavelength of wavefunction graph [closed]
So my professor loves to make like 10 exam questions where we interpret some graphs of quantum wave functions. Now I really do not understand how he reads off the wavelength for instance in these ...
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How to Conceptually Understand Long Wavelength Fluctuations?
I have been trying to conceptually understand long-wavelength fluctuations of degrees of freedom, and I have been reading this (RG) to do so. I understand was it means for a degree of freedom to ...
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Pound-Rebka Experiment
I am new here and have a question.
Does anyone know if the velocity of the photons changes in the Pound-Rebka experiment?
Do the wavelength and the frequency change simultaneously, so that there is no ...
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Why is a receiving antenna optimal at $\frac{\lambda}{2}$, mathematically?
I can understand the qualitative argument of a recieving antenna becoming resonant: An external $E$-field causes the charges to move in a conductor and bunch up, creating a voltage. If the driving $E$-...
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Balmer proportionality
How did Johannes Balmer arrive at
$$
\lambda \propto \frac{n^2}{n^2-4}, \quad (n=3,4,\dots),
$$
and then how did Rydberg mathematically derive
$$
\frac{1}{\lambda}=R\left(\frac{1}{n^2_1}-\frac{1}{n^...
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Wavenumber definition in theoretical physics
I am trying to understand the physical meaning of the wavenumber, which as explained in wikipedia, is the magnitude of the wave vector, which, if I am not mistaken, the wave vector gives information ...
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'Slow variation' in WKB approximation as precise mathematical condition
The WKB approximation provides an approximative solution
to the one-dimensional, time-independent Schrödinger equation
$$ -\frac{\hbar^{2}}{2m} \frac{d^{2}}{dx^{2}} \Psi(x) +V(x)\Psi(x)=E\Psi (x)$$
...
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Photon though a single-slit and uncertainty in the $z$- (longitudinal) direction
Heisenberg's uncertainty principle is sometimes invoked in explaining the width of the diffraction pattern as light passes a single slit. In the case of single photons, when a photon is directed ...
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