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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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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What is the difference of colors of things? [closed]

is there any relationship with The energy of electron? or The wavelength of the light.
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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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Can de Broglie Waves have frequency, just because we know de Broglie wavelength formula? [duplicate]

Sub-question if Yes: de Broglie wave is also often called the matter-wave. While we can find the frequency of an Electromagnetic Radiation from its wavelength $(c=\nu\lambda)$. $c$, in this case, is ...
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Deeper underlying explanation for color-shift in Wien's Law?

Suppose we have a blackbody object, maybe a star or a metal (although I understand neither of these are actually blackbody objects, to some extent my understanding is they can approximate one). ...
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Where does the minus sign go when deriving the Stefan-Boltzmann Constant?

When deriving the stefan boltzmann law from planks law. You may make a substitution (http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan2.html). This substitution will lead to a stray minus sign ...
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What is black green color? What mean “brightness” in physics?

I want to know, what's the difference between green and dark green physically? I know the darkness of color depends the brightness of context, but if the brightness of context is fixed, and I change ...
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What is the smallest DeBroglie wavelenth possible?

An electron has a larger DeBroglie wavelength than a proton. An atom has an even smaller one. Is there a limit to how small this wavelength can get? If so, at what particle size is that wavelenth ...
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Why is refraction of light at a boundary wavelength dependent, and are the two proportional? [duplicate]

Just wondering, why is it that blue light will refract less than red light, i.e. why does the fact that blue light has a shorter wavelength mean that it will refract less at a boundary? I read ...
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How would you make a RGB LED equally bright to a broad-spectrum white LED?

Say you had a broad spectrum white LED (all visible wavelengths) and you wanted to make a RGB LED (just red-green-blue wavelengths) that could produce white light of equal brightness to the broad-spec ...
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Can you create white light by combining cyan wavelengths (490-520nm) with red wavelengths (630-700nm)?

Cyan (blue light + green light) + red light = white light, but is the same true for cyan wavelengths ($490-520$ nm) and red wavelengths ($630-700$ nm)?
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Why do higher harmonics have a lower amplitude than the fundamental frequency?

When we pluck a string, it vibrates in all possible modes of vibrations. The lowest frequency possible is the fundamental frequency and it is the most significant part of sound. But why do the ...
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How is the equation for de Broglie wavelength actually derived?

I have seen the equation for de Broglie wavelength derived through equating Einstein's $E=mc^{2}$, and Planck's $E=hf$, using a substitution from $c=f\lambda$ to make things in terms of wavelength. ...
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Why can we equate these two integrals related to blackbody radiation?

I was reading this Wikipedia article which describes how Planck’s Law of blackbody radiation is derived. Letting $B(v,T)$ represent the energy emitted at frequency $v$ and temperature $T$, the article ...
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What's the difference between Hard X-rays and Gamma-rays?

So I'm aware of this and this, but the question is Are Hard X-rays and Gamma-rays the same thing? If not, then what would be the key difference between them. Moreover, How much would the properties of ...
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Why does frequency of a wave depend solely on its wavelength?

On Wikipedia it was stated that a wave's speed $v$, wavelength $\lambda$ and frequency $f$ are related by the identity $$v(\lambda)=\lambda f(\lambda).$$ The function $f(\lambda)$ tells us that the ...
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Question about spectrum emissions

I was studying about spectrum emissions but I have a question. For example if I have $2$ electrons from different atoms with different distances from the nucleus, then I hit them with fire causing ...
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“Mechanical Detection and Measurement of the Angular Momentum of Light” make the photon have the same wavelength?

Beth used quarter plates and measured the angular momentum of light. I am curious if the light loses some of its energy - when passing through the plates and get rotated with its electric and magnetic ...
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What is the longest wavelength ever measured for a Black Body?

As said in the title, I am curious about the reported measurements for cooled black bodies. Any source is welcome. I am neither interested in any thought experiment nor in the well-established law of ...
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Why do we replace $c$ (speed of light) with $v$ in de Broglie's equation? [duplicate]

Deriving de Broglie's equation (as per my text and teacher) involves equating $E = mc^2$ with $E = h\nu$, where $\nu$ is the frequency. It goes like : $$mc^2 = h\nu$$ $$mc^2 = \frac{hc}{\lambda}$$ $$...
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Why is wavelength of violet colour less than wavelength of blue colour?

The wavelength of light of specific colour increases as we go from left to right in the visible colour spectrum: "VIBGYOR". Wavelength of green lies between wavelengths of blue and yellow. To me, ...
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Diffraction of sound - long versus short wavelengths

I am having some problems finding an explanation why long sound wavelengths travel around objects easier than short ones, hence making lower frequencies audible across longer distances. Most online ...
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Why is it easier to bend a note down on a brass instrument than it is to bend up?

When playing a brass instrument, on a given harmonic, you can bend the pitch above (to a higher pitch) and below (to a lower pitch) where it sounds the best (while staying on the same harmonic, with ...
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What determines whether colors you can't see are visible or not?

So, when someone is red-green colorblind, the colors appear the same to them, like this: And if you're totally colorblind, then things presumably just appear like they would in a black-and-white ...
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De Broglie relationship [closed]

What wavelength De Broglie relationship represents, if particle's motion is given by its group velocity (which is superposition of waves of many wavelengths)
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Is there any upper limit for de broglie wavelength due to zero point energy?

We know that the lower the momentum a particle has the higher will be its de Broglie wavelength, so is there any upper limit to the de Broglie wavelength of electron or any other particle due to the ...
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Does modulating a laser source change its color?

Hopefully you guys can solve this hypothetical for me. Suppose I have a laser which emits light at frequency $530\mathrm{THz}$ with a very narrow spectral width $1\mathrm{Hz}$. From signal theory, ...
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Counting number of Antinodes for Modes in 2D

In 1D cases for standing waves, if we have the 3rd harmonic on a string of length L, then there are 3 antinodes and 2 nodes in between. This means, for each wavelength, we can establish a relationship ...
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Question about dispersion relation

I'm confused about the nonlinear dispersion relation like $\omega(k) ∝ k^2$. Does this kind of wave have multiple frequencies? I have always considered the linear dispersion case, $\omega(k) ∝ k$, ...
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1answer
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Why do small particles deferentially scatter colors (i.e scatter more blue light than red in Rayleigh scattering) while larger particles don't?

In both small and large particles, light as an EM wave will accelerate charged particles such as electrons and induce a dipole forcing the electrons to oscillate at the same frequency of incident ...
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Why do matter waves show refraction? / Why does wavelength change when a particle enters a medium?

I know why electromagnetic waves show refraction but matter waves? I found this in section 2-5 in “An Introduction to Quantum Physics” by French and Taylor while reading about Davison and germer ...
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Why viruses cannot be seen?

With the coronavirus pandemic, a lot of websites are publishing articles about viruses. In particular, I've seen some of these stating that viruses cannot be seen because they are so tiny they cannot ...
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Why is there a concept of photons? Isn't it just EM waves at a certain wavelength?

Visible light is simply part of the EM spectrum at certain wavelengths. I assume UV and infrared don't even qualify as "photons". So why do we have this concept of a photon when all it is, is a ...
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Why does the black body radiation theory apply to many different objects?

The standard theory of black body radiation that I am familiar with derive the Planck's law assuming first that we deal with a box in which the photon gas is contained. The box has a small hole in it ...
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Is the wavelength of matter proportional to momentum or uncertainty thereof?

I am confused about de Broglie waves and their relationship with the uncertainty principle. Both have similar formula and seem to be the same thing with a slight conceptual difference. De Broglie ...
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1answer
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Sun light and leaf color

Wien's displacement law : $\lambda_{peak}T=2.898\times 10^{-3}m\cdot K$ Temp of sun = 5000 so sun radiate green wave in max volume. but atmosphere of earth refract sun light and blue wave is max ...
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Question regarding open and closed air columns

I'm studying high school physics and I've encountered this question: An air column that is open at both ends has a distance of 24.0 cm from one resonant length to another. What is the wavelength ...
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What really determins the color of light? [duplicate]

I have been considering this problem: Colour is characterized by which of following character of light? a)Frequency b)Amplitude c)Wavelength d)Velocity Different websites claim ...
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Intuitive explanation for why blue light is refracted more than red light? [duplicate]

I understand the equation explaining angles of refraction related to wavelengths. But I'm looking for a more intuitive approach/visual explanation? Perhaps related to QM?
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How can a red light photon be different from a blue light photon?

How can photons have different energies if they have the same rest mass (zero) and same speed (speed of light)?
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Why are there no even harmonics in a closed pipe?

I have seen a diagram on sites such as hyperphysics.com that show that there is a missing bit every time so that it makes every harmonic odd. I was hoping I could get a more intuitive explanation. We ...
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Which formulae should I use when calculating the frequency of an electron given its speed? [duplicate]

If I know the speed of an electron, how should I go about calculating its frequency? For example, if the electron was travelling at $v$ $ms^{-1}$ there are two options I could take. Calculate the ...

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