A transition by which the energy of at least one photon is completely transferred to a material.

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Absorption spectra of molecules library

Do you know where I can find a library with absorption spectra? I would like it if then I could input a wavelength and get back a specific value. More specifically I would like to see the absorption ...
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29 views

Different width of spectral lines for different groups of stars

As seen in an HR-diagram, a certain stellar classification can correspond to more than one group/sequence of stars (G5 could for instance be either a giant, main sequence star or a white dwarf and so ...
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Why can't electrons absorb any energy (i.e. absorb some energy of the photons necessary and emit the residual)?

Recently I had a question in mind about the absorption of photons. Why is it that only specific energy levels can be absorbed by electrons? I mean, I get the idea that electrons in an atom have only ...
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88 views

How do Black Bodies Absorb and Emit Radiation? [duplicate]

I have learnt how the gases of elements are able to absorb only certain wavelengths of EM radiation corresponding to the energy transitions between energy levels of orbitals. Furthermore, these ...
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37 views

Photon absorption in a medium - basic principle?

I am trying to understand the basic physics of photon absorption in a medium. Take the example of oxygenated hemoglobin (red curve). Clearly at different frequencies/energies relatively more or less ...
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4k views

Why do X-rays go through things?

I always heard that the smaller the wavelength, the more interactions take place. The sky is blue because the blue light scatters. So why is this not true for X-rays, which go through objects so ...
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24 views

Relationship between oscillator strength and cross section

In the context of absorption of photons by atoms, I have come across two seemingly very related quantities, cross section and oscillator strength. In the book Physics of the Interstellar and ...
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62 views

What is the difference between a white object and a mirror in terms of heat absorption?

Will a white object be cooler than a mirror when exposed to direct sunlight? Or will it be the other way around? If mirrors bounce all visible light and some of the other elements of electromagnetic ...
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21 views

Mie theory: Interpretation in terms of intensity

I'm trying to understand Mie theory. For this I'm reading the book "Absorption and Scattering of Light by Small Particles" by Bohren and Huffman. The derivation of the formulas is fine, but I'm stuck ...
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42 views

How much ionizing (carcinogenic) radiation is one exposed to on a commercial flight, what are the sources, and how could exposure be minimized? [closed]

I don't know if this is the best place to ask this question, but I figure a physics-based answer would be the most satisfying. I'd be happy to be convinced I'm being paranoid about protecting an ...
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81 views

Why are UV protective eyeware Orange?

Many industrial processes use uv as a curing agent. When one uses such a process, one must protect one's eyes from the radiation. Most uv protective gear I have seen is tinted orange? Does this ...
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37 views

Why do different color materal differ temperature in the same sunlight?

I have a blue, red, and green cup and put a thermometer in each. Of the 3 the blue cup had the coldest temperature inside, then green, then red. I understand there may be differences in the ...
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69 views

Water vs. Air : Heat Absorption/Capacity

I am not a physicist by any means and not even a current student, but nonetheless I am looking for an answer. Here is what I have gotten so far from university websites and other various resources on ...
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12 views

Light scattering and absorption in material

I would like to get your inputs on a way for measuring light characteristics (scattering + absorption) in a specific tissue. My aim is to compare characteristics at different wavelength vis and nir. I ...
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100 views

How does absorption of light by atoms and molecules work?

I found this question on a hobby science forum (mainly about chemistry) and found embarrassingly that I couldn't answer the question. A few searches along the lines of 'photons absorption' here on ...
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37 views

How exact does the wavelength of light have to be to be absorbed by an atom? [duplicate]

I have been reading sources such as this on absorption and emission which make statements such as: The interesting thing is that each atom will only absorb photons with exactly the right energy. ...
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157 views

How precise must the energies match for absorption of photons?

According to Quantum Mechanics, in order for an atom to absorb a photon the energy of the photon must be precisely that of a "jump" between energy states of the atom. How precise must it be? If I ...
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70 views

Light absorption, reflection and transmission [closed]

I was bothered by some explanations in the internet about light. Can someone correct me or answer my questions regarding on how electrons react when hit by a photon in different situations: ...
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34 views

Can materials near absolute zero absorb more neutrinos than at higher temperatures?

I was thinking about how in materials near absolute zero the debroglie wavelength of the electrons in the atoms is very large, and it occurred to me from physics that one reason why neutrinos are not ...
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20 views

Is absorption imaging in ultracold gases (BEC) a method destructive of the system?

As of title, I wonder whether this imaging method heats the gas up to the loss of quantum coherence. Let's consider a specific example, a gas of 87Rb (Rubidium) and its D2 line. I might be wrong in ...
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72 views

Can an absorbed photon be emitted as two photons?

I am taking an intro to astronomy class, and have touched upon absorption and emission lines and etc, the prof asked this question in class and got me thinking. I would want to say no, because one ...
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1answer
45 views

Sound insulation, absorption and diffusion. Can they be part of the same process? [closed]

I understand that insulation, absorption and diffusion in acoustics are different concepts. Notwithstanding, would it be correct to assume they may be part of the same process when all are used to ...
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50 views

absorption spectrum of aluminum

I am trying to find the absorption spectrum of aluminum but only can find reflectivity of it and other optical properties. It is easy to find absorption of aluminum oxide, foams etc. but not possible ...
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Do you know if you have zerovalent iron nanoparticles in liquid how to measure minimal magnetic force required for separation of these nanoparticles?

I think of measuring mag susceptibility from VSM data (magnetization divided by the applied field) but I am not sure if this would be enough. Maybe if I employ SQUID measurements, but in that case I ...
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14 views

How is the Lyman alpha forest and Gunn-Peterson trough evidence for Reionization? [duplicate]

I'm trying to understand how the Lyman alpha forest and Gunn-Peterson trough are evidence for Reionization. From what I've read, the Lyman alpha forest tells us how much neutral hydrogen is in the ...
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31 views

Why does vertical polarizer absorb the vertically polarized waves?

They explain that vertical wires serve as the secondary transmitter: the waves induce since oscillations of electrons in the wire effectively absorbing the wave. Ok, let's believe that wave is ...
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35 views

Book on spectroscopy (line dependency on parameters)

I am trying to find a book (undergraduate level) on Spectroscopy. I am interested in how molecular absorption lines depend on parameters like temperature and pressure (for example with gases). Can ...
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28 views

What exactly makes transmittance of graphene change from linear to exponential?

Up to 5 layers, the transmittance of graphene is linear (2.3% per layer): (source) Beyond 5 layers (I assume) the transmittance is exponential, following Beer–Lambert law. What gives rise to this ...
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45 views

How does different particle size account for different colors?

I understand how objects have color in terms of absorption and reflection; however, in stained glass, various nano-particles can have different colors depending on the particle size. As described in ...
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47 views

Bandgaps of Silicon and their application in active optical elements

I know that silion has an indirect bandgap at $E = 1.12 \, eV $ or $ \lambda = 1.107 \, \mu m$ and I have read that active optical processes like absorption and emission have a decreased likelihood to ...
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90 views

How Much Does Roof Color Affect Energy Consumption?

I'm not sure whether this is off-topic; if so, I do apologize and will fully understand votes to close. That said: I live in a climate that's quite cold much of the year but gets pretty hot in the ...
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30 views

Modeling total absorption using absorbance of multiple visual layers

I have a question involving light absorbance versus absorption. It applies to a stack of different photoreceptor types. I understand the difference between absorbance, which is basically equal to ...
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1answer
10 views

Sound range and depth it travells whe it hits sound

I know most people hear from 20hz to 20000hz and about the absorption spectrum of water absorption spectrum of water link but how deep does sound travel when it hits the skin and which range of ...
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199 views

Can a photon be absorbed by a proton?

When incident light passes through a hydrogen gas, for example, does it have 50% chance (since it's a 1:1 ratio of protons to electrons) of getting absorbed by the proton? Any chance at all? If no, ...
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78 views

Implementing Beer's law in a ray tracing render engine

I am a 3D artist and i work in the cycle render engine which is a ray tracing render engine. I want to Implement Beer's law in my transparent materials. I tried to do this based on my understanding ...
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53 views

The properties of light photons [duplicate]

Please consider a closed room with light reflecting walls and in the centre of the room there is a Lighting Bulb. Now if I switch on the bulb, the room is obviously illuminated with light. When I ...
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31 views

When light is reflected, if some of the light is absorbed in the particle, does it change the particle?

Which color/frequency of the light is absorbed and which part is reflected? How is it determined which part will be absorbed? Does that depend on the particle? N.B: When I say particle, please keep ...
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247 views

How does one account for the momentum of an absorbed photon?

Suppose I have an atom in its ground state $|g⟩$, and it has an excited state $|e⟩$ sitting at an energy $E_a=\hbar\omega_0$ above it. To want to excite the atom, one generally uses a photon of ...
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326 views

How can metals absorb light?

We're told that semiconductors have a bandgap and photons of an energy greater than the bandgap can be absorbed, exciting electrons from the valence band to conduction band. This therefore defines ...
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41 views

Why do high altitudes have larger diurnal temperature variation than lower altitudes?

It seems like the lack of atmosphere should not be playing a role in the diurnal temperature variation because that's what makes it colder. Mountains are not that dry, usually.
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Can a photon that matches the energy gap pass through a molecule?

I've heard that atoms and molecules are made up of mostly empty space. I've heard that electrons exist as a probability cloud around and/or between atoms and molecules. My question is, is there a ...
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31 views

Absorption Magnification

I'm working on an optical project about the absorption of glass sheet and I need to measure the intensity of laser beam that has passed the glass sheet and compare that with the intensity of laser ...
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143 views

How to calculate the Refractive index of a glass sheet

My question is how to find the $n$ of a glass sheet with just aiming a laser beam to that. I've got lot of ways that let me find the $n$ ( Refractive index ) but I need the whole part of the ...
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272 views

Light Absorption of a glass

I've the $n$ (refractive index of the glass sheet ) and $t$ (the thickness of the glass sheet) with this information, how can I find the amount light absorption of the glass sheet?
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152 views

Is the Energy of an absorbed photon exactly the energy of the band gap?

I was wondering, if the Energy of a Photon which is absorbed by an Electron, hast to be exactly the Energy of the bound gap. So if i have two energy levels in an atom $E_2$ and $E_1$, does my ...
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42 views

What forms does the energy of a photon get converted to after absorption

Assume an object which has a high absorption rate of light. Now my question is, if you shine light on the object, what all forms of energy does the object acquire? I know there will be an increase in ...
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180 views

Why does the light instantly disappear when we switch off the source?

For example i take a box which is completely covered by the most perfect mirrors possible inside and inside that box i have a bulb whose bulb holder is also covered with the most perfect mirrors ...
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Why do lines in atomic spectra have thickness? (Bohr's Model)

Consider the atomic spectrum (absorption) of hydrogen. The Bohr's model postulates that there are only certain fixed orbits allowed in the atom. An atom will only be excited to a higher orbit, if ...
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838 views

Test whether a glass prevents you from getting your Vitamin D portion?

I work in an office with glass, which I believe filters the UV radiation of the sunlight. Is it possible to test if exposure to the light coming through the glass will supply Vitamin D for me as a ...
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Where do photons go when they are absorbed?

The answer I usually get (and I'm paraphrasing here) is that they disappear and are instead absorbed as heat energy. But I find it hard to believe that the photon simply "disappears." Common sense ...