# Tagged Questions

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 ...

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### What role does wavelength play in the identity of a photon? [duplicate]

According to this question: What determines color -- wavelength or frequency? It is the energy, and thus the frequency of a photon $E=hf$, that determines where it lies in the electromagnetic ...
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### Why does light bend?

I have just read about dispersion of light by a prism and the thing which i donnot understand is that WHY does the light bend at all? Through prisms and slabs? I came to know that red light has the ...
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### FWHM of different spectra and separation in fine structure

I'm doing some research on spectroscopy and there are some phenomena I can't explain (only a second year physics student). I took some spectra of neon in the 659.89529 nm and then of hydrogen at 656....
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### objects and particles react to wave

Is it possible for a wave to be have a wavelength so small that it doesn't interact/affect an object? Like if it is smaller than the atoms itself will it still affect them? I am talking about a wave ...
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### Angular frequency integral to wavelength integral

I have this integral $$\bar{\omega}^2 = \int\limits_{-\infty}^{\infty}\omega^2|\tilde{F}(j\omega)|^2\frac{d\omega}{2\pi}$$ and I want to convert it to wavelength domain $\lambda$. I know that the ...
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### Expression deduction for energy density per wave length

Energy density per frequency is defined by Planck formula as: $$u(\nu,T)=\frac{8\pi h}{c^3} \frac{\nu^3}{e^{\frac{h\nu}{kT}}-1}$$ The relation between wave length, $\lambda$, and frequency, $\nu$, ...
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### De Broglie wavelength of a massive particle as v approaches c

We understand that from a relativistic version of De Broglie's wavelength-momentum relation that as velocity approaches 0 the wavelength trends to infinity and as velocity approaches the speed of ...
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### Why we use wavelength to divide light into rays, wave and particles?

I want to ask something about light, light can be defined as ray, wave, or particle. The group formed because of the wavelength, if the wavelength is less than the dimension of equipment it is grouped ...
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### Why do you need debroglie wavelength less than nucleus diameter to probe a nucleus via deflection? [duplicate]

e.g. you need to give enough energy to electrons to probe a nuclear structure via deflection.
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### How to Vary the wavelength of UV CFL? [closed]

I have a $12$ $V$ $DC$ operated UV $[CFL]$(http://en.wikipedia.org/wiki/Compact_fluorescent_lamp) with $365$ $nm$ wavelength. I need to vary this wavelength in the $250-300-350-400-450-500$ $nm$. ...
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### Explanation for the spectrum of the sun?

My Question is, why exactely does the intensity vanish below 240 nm ? If i look at the plank's law, obviously the intensity for $\lambda \rightarrow 0$ and $\lambda \rightarrow \infty$ will vanish, ...
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### Can an atoms energy levels be changed by changing the de Broglie wavelength of electrons?

So an electron can only orbit a nucleus where its wavelength makes a standing wave, leading to discrete energy levels in atoms. But the de Broglie wavelength of an electron = h/mv. So the wavelength ...
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### What is the significance of wavelength when referring to light (in layman's terms)?

Without any equations or complex terminology, I simply want to understand in complete layman's terms what the significance of a single photon's wavelength is. People say that microwave radiation's ...
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### Kinetic energy as $\pi k_B T$

In the derivation of the Thermal De Broglie Wavelength on Wikipedia, I come across the following: "In the nonrelativistic case the effective kinetic energy of free particles is $E_K=\pi k_B T$ https:...
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### A heavy rope is attached to one end of a lightweight rope [closed]

If one end of a heavy rope is attached to one end of a lightweight rope, a wave can move from the heavy rope into the lighter one. (a) What happens to the speed of the wave? (b) What ...
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### Physical meaning of wavelength of an EM wave

What is the physical meaning of the wavelength of light? This question has been asked before but I cannot find a satisfactory answer. Some respondents have said that the question is vague, I don't ...
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### What is the wavelength of a hot metal when its temperature 400 C? [closed]

I would like to know what will be the wavelength of a hot steel which temperature is 400 degree C
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### UV absorption decrease with an increase in concentration

I am working on a project measuring the absorbance of a solution which contains surfactant and hard brine. The solution has a constant concentration of surfactant and varying concentration of hard ...
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### What is the most common photon wavelength in our observable universe (not including the Sun)?

Ignoring the Sun, what is the most common wavelength of a photon that is received by us on average? (I am not asking what is the average wavelength, but rather what is the most common wavelength ...
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### Variable wavelength LED

Does there exist a type of LED (or other type of light source) that can change it's wavelength depending on the current/voltage it receives on a second wire? If not, would something like this even be ...
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### Why does sound wave suffer more diffraction than light waves generally?

Why do sound waves suffer more diffraction than light waves generally ? I would like more of a logical explanation rather than mathematical .
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### Wavelength vs Wavenumber etiquette

When am I supposed to use the terminology of EM "wavenumber", instead of "wavelength" (or frequency)? The concepts of wavelength and frequency are no problem for me, but wavenumber (number of ...
679 views

### What is the physical significance of Compton wavelength?

Wikipedia says, The Compton wavelength represents the quantum response of mass to local geometry. What does it actually mean?
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### Different colors and Metamerism

Given the following graphs: They describe the response for two different colors . In addition that both colors are metamerism. My question is why? how can I prove it? Thanks
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### If photons don't “experience” time, how do they account for their gradual change in wavelength?

It is often said that photons do not experience time. From what I've read, this is because that when travelling at the speed of light, space is contracted to infinity, so while there is no time to ...
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### Huygen's principle and why can't we see atoms with light

First of all, I'd like to discuss Huygen's principle. In order to explain waves diffraction, it says that every point in a wave front behaves as a source, so the next wave front is the sum of all ...
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### What is a wavelength of an EM wave physically?

This might be a silly question given I am a physics undergrad, but I was suddenly confused. Usually when EM hit a gap they diffract through the gap. But if the gap is too small, diffraction can't take ...
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### $\sqrt{\frac{\omega ^2}{c^2}-k_z^2}$ in cylindrical harmonics

The radial component of the solution of the wave equation in cylindrical coordinates is $$J_\nu \bigg(\rho\sqrt{\frac{\omega ^2}{c^2}-k_z^2}\,\,\bigg).$$ But I always thought that $\frac \omega c$ ...
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### How do we know the boundaries of a wavelength?

So the length of a wave is the distance between two compressed regions as shown in this representation of a longitudinal wave: But how do you know exactly where the two points are? Is there a point ...
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### Uncertainty principle

I am reading about uncertainity principle. My textbook says, if $λ$ is the wavelength of the radiation used to observe the particle then the position of the particle cannot be determined with ...
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### How to actually determine the Index of Refraction of an object in different colors of light?

I would like some guidance as to how the IOR of an object is determined in different colored lights. Taking for example diamond, I know that the base IOR is 2.417, and the respective wavelengths of ...
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### Why can microphone be much smaller than wavelength of sound?

For sound from 20Hz to 20kHz, wavelength is 17m to 17mm, for sound at 2kHz, wavelength is 17cm. And I saw tiny microphone which is much smaller than that. In electromagnetic, there is a smallest size ...
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### How to measure the wavelength of a laser pointer?

I'm working on something and I need to know the wavelength of the laser pointer that I'm using. Can you suggest me a way, using some optics formulae, or anything else to calculate the wavelength?
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### Is sunlight truly white?

I recently purchased a book on nuclear astrophysics, with no goal of mastering the topic but merely to read in between exams and hopefully learn something, it is revealed that the sun is composed ...
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### Why do microwave ovens use radiation with such long wavelength?

According to Wikipedia: Consumer ovens usually use 2.45 gigahertz (GHz)—a wavelength of 12.2 centimetres (4.80 in). Typically, I put the dish inside the oven in its center. I suspect most ...
337 views

### Does each photon have a unique wavelength?

Since the frequencies (or inversely, wavelengths) of photons are part of a continuous realm, doesn't this mean that no photon has exactly the same frequency? Two photons might have the same apparent ...
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### Is there an infinite amount of wavelengths of light? Is the EM spectrum continuous?

The electromagnetic spectrum is a continuum of wavelengths of light, and we have labels for some ranges of these and numerical measurements for many. Question: Is the EM spectrum continuous such that ...