Absorption Definition and 534 Threads

Does it work like that.. that a changing EM field in-phase (actually, like.. 180 degre (spell?) out-of phase) with the incoming photon would absorb it? .. when sound waves of 180 degre.. (spell) out of phase with each other would cancel each other out. The same thing would happen with EM...

I have a question. We claim that the wavelength of a photon must exactly match the difference between the states of an atom or molecule. Then why are the peaks in the absorption spectrum of chlorophyll so broad? Shouldn’t they be very sharp?

I have a 3D graphics book, which gives the formula for absorption of radiance along a ray. I am trying to derive the details and would like to see if my derivation is correct. Let o(p) be the probability density that light is absorbed per unit length at point p. They give the formula as...

For an upcoming experiment I was given the following formula to study It shows the collisional radiowave absorption in the ionosphere although I don't really understand what it means. I have not come across it before and its not in my textbook. Can someone familiar with it please explain to...

How can I tell the difference between a free electron that's absorbed one photon at E = hf and a free electron that's absorbed two photons at E = .5hf? If a photon at frequency f represents a '0' and a photon at frequency .5f represents a '1', then I could send out '11', have an electron...

Hello! Mercury vapour detection is normally performed at 253.6 nm, which is the lowest emission line in the UVC range. I have to figure out if a similar atomic absorption approach would be valid at a longer wavelength, specifically at 365 nm, which is an other emission line but into the UVA...

Hi guys (and girls;)) I need your help... I really don't get the difference between a PhotoLuminescence and Absorption experiment. What kind of informations one can get from each experiment? Moreover, why generally photoluminescence experiments are carried on at low temperatures? Thanks...

Hi All, I've read the reason for longer radio waves being absorbed by the ionosphere more than shorter waves and the argument goes like this: The longer waves cause the ions in the ionosphere to travel a longer distance during a typical RF cycle because the time subjected to the electric...

Correcting Galaxy Luminosities for Absorption ?? As light from distant galaxies traverses deep space towards Earth, some amount of that light is absorbed by various features lying between that emitting galaxy, and Earth receivers. Those features imprint those galaxies' observed Spectra, with...

Could anyone help solve a problem how to find absorption lines in hydrogen atom from n=10 (n - principal quantum number). I know that not all quantum jumps of an electron in atom are possible, thus I don't know how many different emission lins will be from this energy level where n=10.

What does word "absorption" mean in the intestine? Water is absorbed in the intestine. most water reabsorption take place in colon. When they water is absorbed in the first sentence, do they mean water moving out from the intestine to blood vessels. When they say reabsorption do they mean...

Hello I am looking for a few textbooks to digest, I am learning the fundamentals of spectroscopy, in particular absorption spectroscopy of gases. Are there any great textbooks out there on these subjects? I feel I need a more solid grounding. Any undergrad would be welcome, as would any...

Energy "absorption" Hi, Apologies if I've misinterpreted / mis-read something here (not a physics student - just a general interest). Just hoping to be put straight on something fairly simple: Are atoms / electrons able to interact with waves ie microwave / radio waves? If so, are there...

Can anyone briefly explain that what is saturated absorption? What's the condition to have saturated absorption?

the way i understand it is photons excite atoms, causing them to increase in energy. i view this increase in energy as jostling of a atom causing more movement of its proton, neutrons, electrons. i realize a photon is a particle and a wave(in limited comprehension.) so should i view the...

If there is a "red" color ball people told me that if i shine white light on it the "red" color ball absorbs all the light and reflects "red" photons hence we perceive it as "red" colored Is this true? if this is right i want to know more details... what does reflect mean here? what does...

I have been wondering lately, as I am quite new to physics. If an atom dropped from it's first energy level back to it's ground state, and emitted a photon. Could a photon of the same wavelength excite the atom back to it's first energy level? What is the difference between emission and...

If I have a group of atoms in a high voltage field, and I want to use photon energy to aid the ionization of the atoms what wavelength(s) would best be used to have the highest ionization efficiency? The shortest wavelength available? Or the resonant wavelength for each excitation level?

My question concerns my understand of the mechanics of the absorption of Photons by the components of atoms. I will use a common real-world example to facilitate my understanding of the concept. 1. When a rock (for example) sits in the sunlight, the rock warms to the touch. I believe this...

If you're reading a graph of absorption coefficient(cm^-1) versus wavelength(nm), how can you dtermine if the solution is optically dilute? What about optically thick? Thanks Ben

I just have a quick question. Which way of Atom Excitation is more efficient? Photon Energy which matches the absorption peak(s)? Or Photon energy of a Shoter wavelength than the absorbtion Peak?

Why don’t emission and absorption properties of an atom cancel out such that no such spectral lines are seen. If electrons in atoms are excited from level 1 to level 2 and absorb energy at some specific frequency, why don’t they then emit that same frequency when they fall back down to level1...

Hi, I am designing an amorphous silicon solar cell and i wanted some pointers on how I should calculate the width of the intrinsic layer to get maximum absorption of light into my cell. I have designed my cell with the doping concentrations of p and n layer as 10^18 and 10^15 respectively.

Homework Statement prove that A v (B ^ A) = A Homework Equations V = union ^ = intersection ' = complement The Attempt at a Solution A v (B ^ A) = (A v B) ^ (A v A) (used distributive property) ummm yeah I am kinda lost from here. much help appreciated

I have only taken one very intro quantum mechanics class and the furthest we got was solving the Schrodinger equation for the Coulumb potential of the hydrogen atom. So we solved for the allowed energy levels and the wavefunction for the hydrogen atom. We also learned how using the...

How is the absorption coefficient per unit path length determined for excitation sites in a host crystal with an excitation site density of N and a bandgap of the excitation site equal to the photon energy? What I am trying to determine is how many photons will be absorbed for a given length.

Hi everyone, My very first post after simply using physicsforums as a (very) handy FAQ resource. Okay, so my question is probably pretty simple, but I've been unable to find anything on here already. How does a complex dielectric constant imply the absorption of EM radiation? I...

Question: Is it safe to say that if two photons were to simultaneously come in contact with a single atom, the total energy of the combined photons would be absorbed and then emitted as a single higher energy photon with a direction that is opposite that of the average angle of incidence of the...

Homework Statement A refrigerator is rated at 370 W. What is the maximum amount of heat it can absorb from the food compartment in 1 minute if the food compartment temperature is 0 deg C and it releases heat into a room at 20 degrees C. Homework Equations COP=Qc/W W=Qh-Qc The...

What does the absorption rate of body tissues depend on? For example, at what rates would the rectum, vagina, mouth, and skin be able to absorb a certain chemical? Does it depend on the size of the molecule? If it is water-soluble does that make it easier to absorb? In fact, what makes something...

Does anyone know a good reference for absorption lines in the Earth's atmosphere at visible and NIR wavelengths (if there are any)? For example, perhaps in the range of 3500 Å to 8000 Å? I find that the search terms are too broad to give me reasonable results on ADS. I found some atmospheric...

Hi all, I have not seen a separate section for photonics, so I'll post my question here : Does anyone have measurement data of the absorption spectrum of (liquid) water in the wavelength range of 180 - 250 nm ? Thanks :smile:

hi i m studing AAS(atomic absorption specvtroscopy) technique.using beer"s law i plot a graph bw absorbance and concentration.then how can i make the quantitative analysis of my sample?

I've been wondering, if a photon is very far off any atomic resonances, can it still be absorbed by the atom? or will there be compton scattering? or will the photon pass through the atom? or is there something else I'm not considering... Thanks.

Homework Statement Steam initially at 120 oC is passed into 0.60 kg of water initially at 20 o C, and the total mass of water is just brought to the boil at 100C What is the mass of steam that has condensed? Ignore the thermal capacity of the container and heat losses. Homework...

What is the L-edge of absorption? For example, Si has its L2,3 edge at 99.8 eV? The second atomic shell is L, but what does 2,3 mean? Thanks

Having much difficulty with the problem below. Any direction would be greatly appreciated. A waste gas stream contains .045 mole of ammonia per mole of carrier gas. Its desired to design an absorber using water which will reduce the ammonia concentration in the exit gas from the absorber to a...

How do I calculate the mass absorption coeficient ao lead given the linear absorption coeficient and the density of lead.Which formula do I use in this case??.

I'm going through some notes and came upon a question... So, the absorption sepctrum can be seen when a gas sample is placed in the path of white incandescent light where the light absorbes descrete wavelengths. I read that only some of these absorption lines appear if the gas is cool, but...

I Have been studying a problem involving a two mass/spring system. I have been analysing the system and finding out the frequency at which the vibration of Mass 1 is absorbed by Mass 2 and spring 2. The problem can represent a quarter car system where Mass 1 is the unsprung mass (wheel...

Hey guys, doing some research here on Specific energy absorption of Aluminum 1016 T6 extrusion. 300mm length. I have to try and increase the SEA within this control volume. I have couple ideas, what do you think? I am going to apply a 150N load to the extrusion through compression and compare...

I find now that there are several effects on light that are not explained by QED. This surprises me since Feynman was so fond of saying that it covered nearly all the physics we experience. So I expected to get an explanation for reflection when I watched his lectures or read his book on QED...

Hello! I've got a question that asks what is the most likely reason that my experimental absortion plot for lactate differs from the theoretical. I figured it's simply incorrect volumes transferred via the pippette. Could it be the other chemicals in the solution? Although they're 'not supposed...

Hi guys i have a question about how semiconductor materials absorb photons at less than the band gap energy. Particularly in an indirect material like silicon. Looking at absorption spectra for silicon i expected for it to immediately drop off at lower than the band gap energy ~1100 nm (1.12...

The possible energies of photons is continuous and therefore a photon could have an infinite number of possible numerical values for energy. In contrast all forms of molecular energy are quantized (electronic, rotational, vibrational and translational). Surely the probability of any given photon...

Are the results of Atomic Absorption Spectroscopy affected if the metal were ions? For example, if you were trying to measure the amount of zinc in a sample but part of it was dissolved as ions and other parts were simply solid, would they measure the same absorption or would the ions not be...

What is the device used to measure percent light absorption in pigments? I remember finding the percent light absorption in the pigments of some vegetables for a high school bio lab. I am pretty sure the device used was not specific for pigments. The device was user friendly- we just stuck...

The compositions of nuclear reactors are often stated in volume fractions. i.e the fractions of the volume of some region that are composed of particular materials. Show that the macroscopic cross section for the equivalent homogeneous mixture of materials is given by ∑a = f1 ∑a1 + f2∑a2 +...

hey, I'm starting this experiment regarding Sound absorption, and I am having a little trouble finding sufficient research to describe the physics behind it. Basically, I have a wooden chamber, which i will be testing inside. I will have a signal generator at one end, and a microphone hooked up...

Homework Statement If the ratio I(K\alpha)/I(K\beta) before filtering is 7.5:1 for a copper target, then compute the thickness of a nickel filter, that would increase this ratio of 500:1. Mass Absorption Coefficients (cm^{2}/g) Cu: \rho = 8.93 g/cm^{3} K\alpha (0.1542nm) \mu/\rho...