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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Is there a discrepancy between deBroglie's equation and the standard electromagnetic spectrum chart?

I learned that the wavelength of any particle, but particularly a quantized particle, is proportional to its momentum; that is to say, small particles have large wavelength properties and large ...
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How can i add one wave to another? Is the the first waves amplitude different from the seconds? [closed]

There are two tuning forks, one having the frequency equal to 460Hz, second one having the frequency equal to 464 Hz. They are hit simultaneously. Adding the first wave to the second one what is the ...
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Can the energy of a photon be increased, thereby decreasing its wavelength and increasing its frequency?

I know about Inverse Compton Scattering, but is it theoretically possible to take photons with frequencies so low they cannot be detected, increase their energy and hence make them detectable?
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Why don't we observe quantum effects for large massive objects at rest? [duplicate]

The de Broglie wavelength of any massive particle is $\lambda = \frac{h}{p}$. We know that if a large object (say, a baseball) is at rest, it will have $p=0$ and hence $\lambda$ will be infinite. This ...
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Wavelength of reflected light vs transmitted light [closed]

In the basic setup of the experiment below, the transmitted light is used to infer the absorbed wavelengths. The explanation of the experiment states that a high transmittance reading for a specific ...
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How to explain mobile phone rings inside microwave oven?

So finally tested myself and found: mobile phone rings inside microwave oven. Microwave oven frequency is 2.5 GHz which gives wavelength of 12 centimeters. Cellular network waves are even longer. Thay ...
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Could we see through objects if our eye could detect other wavelengths of light?

We see objects around us because light reflects off the surface and enters our eye. So if our eyes could see a wider range of the spectrum (maybe lower wavelength as they would scatter less) then ...
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Is there any way to differentiate UV light from visible or IR light?

I'm working on a small sensor system that responds to only UV light and I wanted to know that is there any way to differentiate between UV light and the rest of the spectrum like using lens if so then ...
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If most types of practical lasers produce a large number of half-wavelengths, then how are they practical for use at all?

I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following: Axial (or longitudinal) modes are determined by the geometrical fit (or ...
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DoubleSlitExperiment: Will a laser beam in front of the slit dramatically change the trajectory of the incoming electron?

Let say we believe that we can get 'which-path-information' so put a laser beam of best matching frequency in front of only one of the two slits so it can deflect the electron in direction the laser ...
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Converting one form of Plancks law to another [duplicate]

Wikipedia says: ...the spectral radiance of a body, B, describes the spectral emissive power per unit area, per unit solid angle for particular radiation frequencies. The spectral radiance of a body ...
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Changes to an EM-wave that is propagating in an inflating space

I am trying to get an easier picture of what happens to an em-wave considering space expansion. My question is: If a star in a non-inflating space emits light recorded at a certain distance of the ...
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Where to use $E=h \nu$ and $p=h/\lambda$? [closed]

Where to use $E=h \nu$ and $p=h/\lambda$? Because both the methods give different answers. Can somebody explain why is it so?
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Differentiating $\nu = \dfrac{c}{\lambda}$

I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following: The coherence time $\tau_c$ over which the emitted wavelengths are considered ...
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Why is the color of light not associated with frequency?

Imagine a green light source is at the center of a transparent material sphere and I am staying in the vacuum (or air) and looking to it. Now imagine that the wave length of the this light increases ...
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Why is the phase difference an “odd number of half-wavelengths” when two waves interfere destructively? [duplicate]

Excerpt from the Feynman Lectures, Volume III, Quantum Behavior (emphasis mine): At those places where the two waves arrive at the detector with a phase difference of π (where they are "out of ...
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What can we expect to observe if we were able to observe de Broglie wavelength of massive bodies?

I have seen the famous question where they ask us calculate the de Broglie wavelength of a moving ball but it comes out to be too small and hence we conclude that it is too small to measure by known ...
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Planck`s law for an interval of wavelengths

Planck's law for spectral radiance of a black body for a wavelength: $$P=\frac{2hc^2}{\lambda^5}\frac{1}{e^{hc/\lambda k_bT}-1}$$ If I want to know the spectral radiance for an interval of wavelengths,...
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What does momentum of Photons mean? [duplicate]

I have already checked out Can a force stop a Photon since Photons have momentum and What does momentum mean when talking about massless particles?, but that didn't answer my query. I already know ...
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How do Fluorescent molecules emit light in a different wavelength than the one needed to excite them?

if it took a very certain amount of energy to excite an atom, how come when it de-excites it emits a photon of lower energy? I know that's what scintillators do, I Just want to know the microscopic ...
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How Small a Slit can Light Pass through?

If you imagine light source passing through a single slit of variable thickness, as you lower the thickness of the slit the light will diffract more and more until the slit is small enough that no ...
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Signal reflections on conductors at low frequencies where they are not transmission lines

This question might be suited for the Electrical Engineering forum, but I think I might get more scientific explanation/discussion (rather than anecdotal) on this forum. Is the reflection phenomenon ...
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Wavelength of an electron in a magnetic field

I came across a problem in which I was asked to find the magnitude of a magnetic field, if an electron was projected into it with a certain velocity perpendicular to the Direction of the field, and ...
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What is the relationship between the classical wavelength of light and the quantum mechanical wavefunction of a photon?

It is common to speak of the 'wavelength' of light. For instance visible light has a wavelength of around 400 to 700 nm. A single photon can also have a wavelength, given apparently by $\lambda = \...
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Validity of hydrodynamic description

Spontaneous thermal fluctuations occur at microscopic level in liquids. It is said that hydrodynamic description is valid in the long wavelength and low frequency limit. So, to depict the thermal ...
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How to calculate frequency in speaker-microphone scenario like this? [closed]

We have a speaker and microphone, distance between them is 10 meters. They are both on 1 meter distance from sound-reflecting wall. Velocity of voice is 340 m/s. It is observed that microphone does ...
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De Broglie wavelength and wave function

Is the De Broglie wavelength of a quantum entity same as the wavelength of its wave function? If yes, why? If no, why? If it is true only under certain circumstances, what are the conditions?
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Why do molecules form band spectrum?

If we observe any textbook they say that molecules form band spectrum. But a H2 molecule is just 2 H atoms and both form line spectra but somehow combination of 2 H atoms formed band spectrum. Because ...
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Kirchhoffs' radiation law

I have a doubt regarding Kirchhoff's law of thermal radiation. From what I found online Kirchhoff's law says that the monochromatic absorptance equals emittance in thermodynamic equilibrium, in a ...
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How do I calculate the group velocity of a waveguide?

I understand that the group velocity is computed by $d\omega/dk$. Given the relationship between the wavelength of a waveguide and its frequency: $$\lambda=\frac{c}{\sqrt{\nu^2-\nu^2_0}}$$ where $c$ ...
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Should gravitational waves quantize similar to photons?

A single photon's energy is given by $E=hf$. This is also generalized to massive particles as $\lambda = \frac{h}{p}$ or $E = \sqrt{m_0^2c^4 + (hc/\lambda)^2}$ (they're equivalent for photons). Having ...
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How to calculate the amplitude of a matter wave of debroglie equation?

I studied the formula that to calculate the wavelength of a matter wave we have to calculate $h/p$ where $h$ is plancks constant and $p$ is the momentum of the particle for which we want to calculate ...
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How do wavelengths add-up?

If I have 3 LED lights of following colors and wavengths: Red 650 nm Blue 450 nm Green 550 nm All three are placed side by side and turned ON.. then what will be the wavelength of the combined light ...
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If the Sun's temperature is around 5000K to 6000K which means it is a yellow star, why does it appear white in space? [duplicate]

If the thermal radiation of stars is close to the thermal radiation of a black body the sun should appear yellow but yet it appears white because of emitting all of visible wavelengths which combine ...
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The connection between the wavelength and the atom level

In my textbook it said the following: Photons with wavelengths in the spectral range of $[94\mathrm{\ nm},104\mathrm{\ nm}]$, interact the hydrogen atom in the basic state. Photons having those ...
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Significance of Group velocity Equation

$$v_g\equiv\frac{\partial\omega}{\partial k}.$$ The above equation is for Group velocity of waves, so what is the Physical Interpretation of this Equation? As we know $k$ is wave number which shows ...
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Prove: $(\Delta x)(\Delta \lambda) \geq \frac{\lambda^2}{4\pi}$

Currently I was going through the formula $$(\Delta x)(\Delta p)\geq\frac{h}{4\pi}$$ which is of course the enclosed form of Heisenberg’s Uncertainty Principle. But I also get this formula $$(\Delta x)...
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How is wavelength of light related to observability?

One of the things I learned from Heisenberg's Uncertainty Principle is that when you try to observe the position of a microscopic particle, you have to use a light of smaller wavelength (which implies ...
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Converting a turbulence spectrum in frequency to wavelength

So, I have a spectrum calculated from an underwater sensor, $S_{vv}(f)$, and want to convert it to $S_{vv}'(k)$, where $k$ is wavelength and $f$ frequency. I assume Taylor hypothesis for frozen ...
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Why smaller wavelengths have higher penetrating power?

I've read that x-rays and gamma rays penetrate deeper whereas greater wavelengths like infrared don't go deep. Moreover, out of the two of radiations (alpha, beta) beta travels more in air on account ...
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What does 'Normalized Solar Intensity' refer to in the diagram below

For the Value Axis (Normalized Solar Intensity) what does the value represent? Is it the Solar Irradiance rate normalized in a specific equation or is it something else?
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Will an absorbed photon always be re-emitted with a different wavelength? [closed]

And if this is the case, what is the reason that the re-emitted photon (when the electron moves from an orbit to a further orbit) has a different wavelength than its wavelength when it was received?
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Why do atoms absorb photons at specific wavelengths and reflect photons at wavelengths other than the absorbed photons?

As we already know that the electron emits light photons when it travels from one orbit to another, and that causes this transition is the electron absorption of the incoming photon. But when the ...
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Does quantum mechanics mean that there are a finite number of colours? [duplicate]

Forgive me if my reasoning is based on flawed logic and information. I am no physics expert. As I understand it when light strikes an object the energy of the photons is absorbed by the atoms that ...
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Gravitational redshift in terms of wavelength

I know that Einstein’s theory of general relativity predicts that the wavelength of electromagnetic radiation will lengthen as it climbs out of a gravitational well. Photons must expend energy to ...
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Superposition and Boundary Conditions in Standing Waves

A standing wave is formed due to superposition of two waves with same anplitude, wavelength and period but propagating towards opposite direction to each other. I would like to focus on how initially ...
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Does velocity make sense if it is small relative to the de Broglie wavelength?

What does it mean if a particle has, say, de Broglie wavelength of $100m$ and a velocity of $1 m/s$? Is it even possible to have such a setup? I don't see why not, since we can always slow the ...
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What is wavelength? [closed]

I know that wavelength is the distance between corresponding points of two consecutive waves. It is the distance over which a wave repeats its motion. But I am unable to understand what is actually ...
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What is the significance of the de Broglie wavelength? [duplicate]

I have just learnt quantum physics in school and learnt the concept of wave-particle duality. But I still have trouble understanding what the de Broglie wavelength is. What does it mean for a particle ...
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De Broglie wavelength of composite systems

Can the De Broglie wavelength of a composite system (like a molecule) be derived as opposed to being calculated from the composite mass? EDIT: @Dr jh, interesting relation you have derived. However, ...

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