Absorption Definition and 534 Threads

I've read that UV light cannot "penetrate" the atmosphere as easily during winter. But what does this exactly mean? My hypothesis is that due to rayleigh scattering, since light with smaller wave lengths scatter more, the UV light doesn't end up reaching the surface of the Earth (i.e. gets...

Is a photon fully absorbed by a electron in metal? Ejected electron is a free electron or bonded one? Is it possible to have a zero work function? If not why? I want to study about this detaily ,can you prefer some reference papers?

Homework Statement If an atom in energy level 1, how many absorption spectral lines can an atom exhibit due to transition between 3 levels? How about 4 and 5 levels? And also in emission? Homework Equations Concept The Attempt at a Solution I am confused one book says it can absorb a photon...

Ok, I'm a bit confused with the spectrum of the Sun. Is the spectrum of the Sun continuous or absorption? Better yet, is it both? Or am I totally confusing myself? I understand that the source itself is continuous but it is partially absorbed (wrong phrasing?) as it passes through the outer...

Why is the absorption coefficient (##\alpha##) of water is always given using the units ##\text{length}^{-1}##, while for other materials it is often given by ##\text{length}^{2}.\text{mass}^{-1}##? For instance, this paper uses ##cm^{-1}## for water and yet ##cm^2 / \mu g## for other...

It doesn't make sense to me that absorption spectra are (mostly) continuous. Here are my beliefs. Please tell me which piece/pieces is a/are misconception(s). 1) When light is absorbed, the energy is used to excite an electron to some discrete energy level. 2) To get to this discrete energy...

I have am currently reading Radiation Detection and Measurement, by Gleen F.Knoll, and in chapter 10 page 309. And have come across something that is causing a bit of confusion, for context the chapter is on gamma ray spectroscopy. So in the text it say's 'Thus the effect of photoelectric...

Hi, I am doing my dissertation for Mechanical Engineering on Solar Stills and my mentor has suggested it would be a good idea to research the physics of light/infrared absorption, transmission, water evaporation and condensation. I am wondering if anyone has good book recommendations for me to...

Which are main absorption modes of matter for gamma rays under about 500 MeV? And how strong is the absorption? For low energies (under 20 MeV) the mechanisms are: 1) Photoelectric absorption - all energies from eV range onwards 2) Compton scattering - all energies enough to displace the...

A gas stream containing 3% A is passed through a packed column to remove 99% of A by absorption in the water . The absorber operates at 25 degree Celsius and 1atm and the gas and liquid rates are to be ##20\frac{mol}{hr ft^2}## and ##100\frac{mol}{hr ft^2}##. Find the ##(NTU)_{OG}## ...

I read somewhere that the "new car smell", which many of us like, is composed of formaldehyde, something that is not good for health. I also learned that it has tendencies to cause pulmonary diseases. A good option to get rid of the smell is to drive with windows down. But doing that in the...

I am trying to plot the absorption curve of a given sample using some spectrophotometric data. The data that I've collected are transmittance ##T## and reflectance ##R## – the ratios of transmitted and reflected light power to incident light power. However, using two different methods I got two...

Homework Statement The total spin of an Mg atom is zero and remains zero after absorption or emission of a photon. To which states can one of the electrons in the outer shell get by absorption of a single photon: 4s, 5s, 3p, 4p, 3d, 4d?2. The attempt at a solution I am not sure which of the...

Which infrared photons can London force bound liquids and crystals of simple particles (atoms, and homonuclear diatomic molecules) legally absorb? For comparison: diamond is bound by strong covalent bonds. The restoring forces permit vibrations about the C-C bonds at about 1000/cm. But since a...

Hi everyone, I have an absorption spectrum that I obtained from a sample after radiation and I need to use the background sample as a reference, how can I do that using excel? what I did is subtract the radiated from the background spectrum then plot it, is that right? Thanks.

Why more emission lines than absorption lines are usually observed in the atomic spectra of most elements hence explain why this occures?

Homework Statement I am conducting an experiment where I am interested in finding the absorption coefficient of different materials as muons pass through them. My data was all well until I realized more muons were measured AFTER they passed through one of the materials, which makes no sense...

What is the difference between the photon interaction mechanisms in emission due to absorption and reflection?

My question is regarding absorption and emission lines. As far as I understand, when a photon of the "right" wavelength passes through an atom, an electron is excited and takes on a higher energy state, in proportion to the energy imparted by the photon. This is the "absorption" part. However...

Homework Statement i'm viewing an example written in class. it looks like this: f(x1, x2, x3, x4) = [(not x1) * x2 * x4] ∨ [x2 * x3 * x4] what should be function after applying absorption law? Homework Equations i know how another option called "gluing" works: [x1 * x2 * x3] ∨ [(not x1) *...

Homework Statement "The 2200 m/s flux in an ordinary water reactor is 1.5*10^13 neutrons/cm^2*s. At what rate are the thermal neutrons absorbed by the water?" Homework Equations (unsure) The Attempt at a Solution I know that absorption of a thermal neutron (a neutron in thermal equilibrium)...

I'm reading Eisberg's Modern Physics and in it, in the atomic spectra chapter, he says: "We have been discussing the emission spectrum of an atom. A closely related property is the absorption spectrum. This may be measured with apparatus similar to that shown in figure (5-1) except that a...

Has the spectrum of light that is reflected off planet Earth ever been measured from outer space? (In the same sense that we measure spectra of the light emitted/reflected from other celestial bodies in astronomy). If so, would it be possible that there could be dips in the spectrum resulting...

Since we know that when an electron goes from the ground state (hydrogen) n=1 to n=3 for example, we have ΔE = E3 - E1 by manipulating the equation we get Rydberg's formula 1/λ= R (1/ni2 - 1/nf2) (where R is Rydberg's constant) My question here, if the electron goes from higher energy state...

Homework Statement An electromagnetic wave is incident on a surface which absorbs all the electric field. Use Maxwell’s equations to determine the magnetic field on the other side of the surface. Homework Equations The Attempt at a Solution My initial thought was that ##B=0## as a varying B...

Hello every one I deposited TiO2 thin layers on glass conductive substrate and then i took there absorption spectra. My question is why do i see interference fringes in the absorption spectra of my samples.

I can just get the idea of a silvered surface reflecting IR and a black surface absorbing IR (analogous to how light behaves) but I can't see how a silvered surface, if warm is a poorer emitter than a Matt black surface, if warm? Would appreciate any help without going too in depth. Regards, G.

Water vapor exists at a higher energy state than liquid water...but does that make a difference in the absorption bands? In other words, are the absorption bands of vapor and liquid water identical? Thanks!

What is the absorption ratio of the water humidity of each in a given period of time, is there any proof?

I've been recently studying the correlated-k method of calculating the absorption of EM radiation when passing through a sample of given thickness. I'm not sure if anyone here has experience on the same subject, but in case there is I have some questions... Suppose I have a material sample that...

Hi guys, Im new here so I am going to get right to it. Excuse my grammer I am on my mobile. So I am trying to understand the difference in absorbance spectra of NAD+ and NADH. I have seen this touched on on this site but not directly answered. NAD+, with an apparent two aromatic structures...

Hi. In physics articles, they say that sun light is white, and contain all colors. But they show say that the Sun's atmosphere absorb light at certain wavelengths, causing the intensity of the light at this wavelength to drop and appear dark. And the absorption spectrum looks like this...

Hello, I would like to calculate the difference between a white surface wall surface and the same kind of wall but with brown outer surface. I would like to know the reflection and absorption indices and then calculate the surface temperature of the wall in the two solutions at the same...

I have this problem: Consider the next state for the EM field: ##|A\rangle=\frac{1}{\sqrt{N!}}\left ( \int e^{-k^2} \boldsymbol{a}^\dagger_{k,+} \right )^N |0\rangle##. There is a particle in the unique bound state for spherical potential ##V(r)=-\delta ^\prime(r)/r##. for absorb a photon if...

It is based on the value of the edge coefficient I obtained, for Germanium at the wavelength of 1550 nm has a value of 459.54 / cm and GaAs at wavelength 885.6 nm has a value of 239.78 / cm. If based on the theory of absorption depth (1 / alpha), then the optimal thickness of GaAs is thicker...

After an electron absorbs a photon, it will move to a higher energy state. It then releases a photon and returns to its ground state. But why does the electron release the photon? Why does it not remain in that energy state? What forces it to return to ground state?

Just a quick question I got in my mind while reading up about fission, the so called Doppler effect which manifests itself in fertile material like U238, I read it helps control reactor stability , hence the majority of fuel consists of U238, as the fuel heats up at some point, U238 starts to...

Hi there, my understanding of absorption coefficients is that harder materials generally reflect more sound similarly to how a harder material will result a ball to bounce higher than a softer material. What I am having trouble finding research on and understanding is the reasoning behind the...

Homework Statement [/B] "Absorption spectra of gaeous HCl show a line at 3.5 μm which results form molecular vibration (oscillation from interatomic distance)" How do I get the frequency of vibration from this? Homework Equations ? If I knew this, then I could probably solve the problem The...

Hi people, i am doing the deconvolution of the optical absorption spectra of some quartz samples . The optical absorption spectra were obtained following a step annealing procedure.For the deconvolution i am using the Origin 9, so my question is.. Why in some articles i find the deconvolution...

Hello, I have a presentation tomorrow and in a segment, I talk about light absorption. It's more conceptual than technical. I did quite a bit of research on the topic but because of simplifying information I may have butchered the facts and written something wrong. Could anyone please confirm/...

Dear Forum: I have a question about atmospheric photodissociation. I use methane as an example, but any atmospheric gas molecule would suffice. Methane, CH4, has a photodissociation energy of 439 kJ/mole at 298oK, meaning that CH4 + hv --> CH3 + H , hv<274nm. It also has an “absorption cross...

A problem I encounter when microwaving food is that the centre is no penetrated by the microwaves so remains cool and I have to wait for the heat to be conducted through which takes a long time and undermines one of the advantages of microwaving which is the speed of the process. Would it make...

What is the formula to calculate acoustic absorption in water? particularly sound in the ultrasonic range.

During the photoelectric process, photons are absorbed and electrons are ejected. In Compton scattering, photons are scattered rather than absorbed. My textbook (Quantum Physics of Atoms,Molecules,Solids,Nuclei, and Particles) explains that absorption occurs in the photoelectric process because...

Hello, I am trying to figure out how much the human skin temperature would increase when the skin is illuminated by radiation of a certain intensity (W/m^2). We can assume that the skin has an emissivity and absorptivity both equal to 1. For instance, imagine the skin illuminated by the sun (I=...

Hi, I read that scattering is just hitting a particle and bouncing off at some other direction. But I also read that scattering involves the complete absorption and emission of a particle/wave. Is this part correct? I have been unable to find that bit of information anywhere else.

Hello everyone I want to know what is the difference between Absorption and Extinction spectra. and in term of experiment how can get extinction spectrum. Thank you

A person working in a company that manufactures absorption refrigerator told me that when Ammonia dissolves in water, the water temperature rises. In short, Ammonia absorption is water is exothermic. If it's true, then what's the reason behind it? Is it due to the fact that the latent heat of...

Hi. I'm trying to model the attenuation (extinction) of a weak laser through a gas sample using the Beer-Lambert law. I've found that the attenuation cross section can be written as the sum of both a scattering and absorption cross section, however I'm having difficulty finding a source that...