# 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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### Photon size vs. Planck length [duplicate]

Another attempt to pose a correct question: with what probability, i.e. a real number in $[0,1]$ photon hits a sphere with diameter the size of Planck length?
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### Planck length and photon [duplicate]

With what probability, i.e. a real number in [0,1],a photon occupies a space of the size of Planck length?
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### Doppler shift and speed of rotating objects in space

I understand the concept of how we can use the doppler effect to know if an object is spinning, in the sense that the part of the object spinning towards us will exhibit a blueshift, and the part ...
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### Does touching the string at nodal points kill all the overtones or kick the string into a higher energy state? [on hold]

I saw a question about string action where the answer said touching the string at a nodal point kills all the higher overtones in the Fourier series! So standing waves 2, 3, 4,... have only one ...
7k views

### How does the diameter of an open ended tube affect the frequency? [duplicate]

I measured (using a software) the fundamental frequency produced in an open ended tube of different lengths. Does the diameter of an open ended (both ends) tube affect the fundamental frequency?
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### Why physics cannot affect cosmological modes whose wavelength is larger than the horizon?

I started to learn cosmology recently. Confused about this point in a book. The book is Modern Cosmology by Scott Dodelson. I am confused about this in Chapter 6 "The horizon grows as the scale ...
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### How do I calculate the relative number of photons per wavelength emmited by the sun?

Assume I generate $n$ photons emmited by the sun. They have wavelengths between 390 and 750 nanometers. How do I find out the number of photons that correspond to each wavelength: How many of my $n$ ...
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### The link between discrete energy level in quantum mechanics and harmonic series in Acoustics

Consider a quantum square potential well with infinite depth: $$V(x)=\begin{cases} 0, &|x|<a \\ +\infty, &\text{otherwise}. \end{cases}$$ Solving the Schodinger equation of a particle with ...
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### Bohr’s Quantisation Condition [duplicate]

I am a grade 12 student from India and my physics textbook does not delve deep in the bohrs quantisation condition but has given us a paragraph to figure out what it is: “Consider Motion of an ...
144 views

### Is there 100% pure white? [duplicate]

Is it possible to have an object 100% pure white without sky blue or sun color tinting the pure whiteness of the photons reflecting/deflecting off an object? Are there any lights that can produce pure ...
162 views

### Filter for RGB separation

Looking at Bayer filter of a typical consumer camera, one can easily see that sensitivity of the filter for each color is all over the place. Are there filters similar to Bayer that do a better job at ...
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### Why are Raman lidars and Rayleigh-Mie lidars operated at those specific wavelengths for aerosol study?

A study of several Atmospheric lidar stations around India shows that in order to study properties of aerosols, all Rayliegh-Mie lidars are operated at 532 nm, and Raman lidars are operated at 355, ...
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### Refractive index variation with wavelength of light

In my book it is written that $$\text{refractive index} = c/v =\sqrt{\text{permeability} \times \text{permittivity}}$$ The dielectric constant medium is dependent on the frequency of the field....
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### Possible to separate audio from separate sources into separate audio streams using multiple microphones? [closed]

I want to be able to separate audio from separate sources into separate audio files. I know that audio takes time to travel, so there could be differences in recording time for the same "woohoo" sound....
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### Wavelength of a particle [duplicate]

As we know wavelength of a particle is equal to (Planck's constant / momentum), so here momentum $= mv$ where $m$ is a mass of an object and $v$ is the velocity of an object. What will happen when ...
34k views

### How do you measure wavelength/frequency of light

I'm sure this is a trivial question for someone who knows something about electromagnetic radiation, but: how do experimenters measure the wavelength/frequency of light? For example, how do we know ...
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### Why does violet light bend the most? [duplicate]

When white light passes through a prism, refraction occurs and it splits into its seven constituent colours. If the spectrum is obtained on a screen violet light appears much more bent than red light. ...
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### Why sky is blue? [closed]

The major factor of different scattering is the ratio of wavelength to the size of particles which are working as microscopic scattering mirrors. In a sparse particle medium like air, the longer the ...
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### Is there no way to create an arbitrary wave on a string fixed at two ends?

My question concern standing waves on a string with 2 fixed end. As there is one wave created, it will be reflected when it reaches one end and create another identical wave with opposite direction ...
340 views

### Radio waves collision versus waves in a pond collision

Please see the attached picture: We are trying to show an image to visualize radio wave collision and interference with regards to Maritime AIS Technology. What do colliding radio waves have in ...
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### Why does the additive color model use red, green and blue instead of yellow, green and violet?

Long cone cells in the human eye are most sensitive to 570-nm wavelengths which are more like spectral "yellow" than spectral "red" and short cone cells are more to 440-nm wavelengths which are more ...
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### Components of wave vector

Is 3-dimensional wave vector defined as $$\tag{1} \mathbf{k}=\frac{2\pi}{\lambda_{x}}\mathbf{\hat{x}}+\frac{2\pi}{\lambda_{y}}\mathbf{\hat{y}}+\frac{2\pi}{\lambda_{z}}\mathbf{\hat{z}} ?$$ If it is,...
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### Are there accepted spectral lines, or wavelength of light emitted, for the various neural and ionized atoms? If yes, where can I find them? [duplicate]

I am working with the redshift phenomena and analyzing the spectral lines of various emissions by galaxies. However, when I came to analyze the change in wavelength I was confused on what to compare ...
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### Why frequency does not change when light passes through the denser medium? [duplicate]

as far as I noticed always people in physics have a predefined assumption that frequency is constant. whereas we know that the c is the outcom of product of wavelength and frequency. we have different ...
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### Deriving Planck's Constant from Wien's Displacement Law

So I'm reading an introductory book on Quantum Theory (David Park, 3rd ed.) and I am having trouble with the following question: "According to Wien's displacement law, the wavelength $\lambda_m$ at ...
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### Why an open tube at both ends suffers resonance? [duplicate]

Why an open tube at both ends suffers resonance when subjected to a sound that propagates through the air with length of where $L / 2$? I already know the methodology to calculate the harmonics in an ...
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### Can application of force contract wavelength of particles

When I put the de broglie relation for momentum in Newton's law F=dp/dt I saw that in some way F is inversely proportional to wavelength. So if we apply greater force, the shorter the wavelength ...
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### Will overlapping two different beams of coherent light with different wavelength cause interference?

If I use two different wavelength lasers to transmit light into a single mode optic fiber will they interfere with each other? If so, how much will be that interference.
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### Effective wavelength

While measuring light from sky or anyother things we use photometer. If current flowing in photometer is proportional to intensity and frequency why there is something called effective wavelengths. ...
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### Heisenberg's Uncertainty Principle - finding uncertainty in wavelength

I am confused about this problem: I needed to find the uncertainty of a wavelength using Heisenberg's uncertainty principle. In the solution, they differentiated $λ=c/f$ with respect to frequency to ...
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### Formation of Red and blue bands in the sky

Today at the time of sunset I saw this The sky is divided into two parts one In red and one in blue which are very distinctive Can anyone tell how? The upper part of the image points towards the ...
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### Are kitchen microwaves in the audible range?

The waves of a typical kitchen microwave oven have a wavelength of 12cm while the audible spectrum is between 1.7cm and 17m, so one might think that they overlap and that kitchen microwaves should be ...
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### Sizes of Elementary Particles

Present observation shows that elementary particles have no internal structure, and have no real size as they are described by wavefunction. Something that therefore confuses me is that on a lot of ...
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### Propagation of wave on a stretched string

I'd like to describe a scenario in which a wave pulse propagates on a string. Consider a long string with one end fixed to a wall and the other held by a person. Suppose the person snaps his hand a ...
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### Wavelength of cosine-squared

I am confused. Usually, the wavelength is the x-distance between the tops of two consecutive waves. Here is the graph. There is only 0.1 m between 2 crests. But the answer counts the wavelength as 0....
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### Database of Color Emissions

I am reading about the color Green and am wondering if there is a database anywhere listing the atoms/molecules/powders/minerals and their color wavelengths in various forms. Basically I would like a ...
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### Wavelength scalar/vector ambiguity?

I have seen the de Broglie relation for wavelength written as $\lambda$ = $\frac{h}{\gamma(\vec{v})m_o\vec{v}}$ I know wave propagation in the one - dimensional case makes wavelength a scalar, as ...
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### What is wavelength at classical turning points using WKB Approximation? [closed]

According to what I know is that a classical turning point in Newtonian Mechanics is a point where a particle has a zero kinetic energy (Total energy is equal to potential energy) and must be ...
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### How to find out the wavelength for the blue led diode?

I need your help as I am stuck and I dont know where to start. I have got four blue leds diode that come with dark blue led lights that I really want to get the same led colours for my 3 fans, but I ...
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### Wavelength and Lattice constant - need to be the similar magnitudes to have interference?

I was taught that they need to have similar magnitudes but I did an exercise last week and the magnitudes were different by 3 decimal places. Before I also noticed them being either the same or maybe ...
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### Momentum of a photon equals Planck's constant over wavelength

A common identity in Quantum Mechanics is relation between the momentum of a photon and its wavelength: $$p = \frac{h}{\lambda}$$ The identity is discussed here, for example: https://en.wikipedia....
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### How can I get the wave number and wave vector? [closed]

$$\overrightarrow{E} = (-10 \hat x + 4 \hat z) e^{-j(2x+5z)}$$ I recently started to study electromagnetics, but I'm having a hard time following up. May I ask how to calculate the wave vector \$\...
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### Blackbody Radiation — Minus Sign Popping Up When Deriving Rayleigh-Jeans Formula

I saw this question: Trouble in deriving the Rayleigh-Jeans formula from the steps shown on HyperPhysics site, but I don't consider it answered, so I'd like to dwell a little more into it. After ...
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### Why doesn't the wave's frequency change as it gets refracted? [duplicate]

I know that frequency means a complete wave produced per second. But when the wave gets refracted, it's wavelength decreases. If the wave's wavelength has decreased doesn't it means that the wave has ...