Absorption Definition and 495 Threads

Hello everyone, Aspirin(acetylsalicylic acid) is a weak acid. So in the acidic PH of stomach it must be more in nonionised form. In the alkaline PH of intestine it must be more in ionised form. Now my note says something is more absorbed if it is in non ionised form, this makes sense because...

I was conducting an experiment, and we had to use a radioactive source and a Geigor counter, in conjunction with aluminium plates. Using the data we produced we had to graph an absorption curve and obtain a value for the mass absorption coefficient of aluminium. Then we had to compare this...

Hi All, this is puzzling me; we have a real part of the refractive index that governs refraction, ie. scattering, and we have an imaginary part, which describes the absorption of the light. The two are related, as you would expect, and a mathematical relationship exists between the two. The...

I have a problem here I am trying to solve for work. Does not need to be 100% accurate. Apple slices are pushed through a bath of hot water to heat the outside of them for 30 seconds. - Apple slice has an area of 3500mm² = 0.035m² - Apple temperature is 3 degree cel - Hot water temp = 53...

why most material absorb EUV-region light? why hard X-ray can go through all material? 【http://galileo.phys.virginia.edu/classes/252/black_body_radiation.html】← here doesn't explain that. Thank you!

Homework Statement X rays give continuous spectrum and line spectrum. Whether these spectrums are emission or absorption spectrum? Homework Equations The Attempt at a Solution I think it is emission spectrum, because there is no absorbing material. Still, i need confirmation from...

Hello! I'm writing a thesis about the optical properties of CO2. However I'm having a hard time finding any solid material about the basic info of the absorption spectrum of CO2. I'm especially interested in the absorption band at approximately 4,3µm. If any of you guys know some good articles...

I know that an atom "absorbs" a particular frequency of energy depending on which element and which electron in this element. The question is (for example) if we take one known emission frequency from a particular element, and use that exclusively to bombard another element for a lower...

hi i am a little bit confused right now. i just read wikipedia about IR-spectroscopy and it is said, that: "In order for a vibrational mode in a molecule to be "IR active," it must be associated with changes in the dipole. A permanent dipole is not necessary, as the rule requires only a change...

Rhodium has been measured and the following values have been obtained for the resonance parameters of a well-isolated resonance Eo=1.26 ev , σo=5000 b , Γ = 0.156 ev , σs=5.5 b , Is there anyone can help me HOW to calculate the thermal absorption cross section ? I'm disparate I don't know how to...

emission and absorption?? confused! hiii, I am just wondering if anybody can give me a very simple definition of each of the two terms, and what the main difference is. Is emission when a wave enters a denser medium (from air to water)? and absorption when a wave enters a medium of lower...

An electron absorbs a photon. Can this be termed as attraction of some kind?

Homework Statement Prove the absorption law A U (A and B) = A Homework Equations The Attempt at a Solution I need to prove the sets are equal. I don't know how to prove the right hand as a subset of the left hand. For left hand as subset of right hand, it's pretty simple (we can define...

hi i was thinking that after the laws of quantum mechanics, where all atoms and molecules have discrete energy states, things like continuous spectrums should be forbidden. but why are there still molecules like chlorophyl which show this property? i would think, that this means, that the...

What does it mean if one found negative absorption in uv-vis absorption graph?

How is a photon absorbed by an electron? Do the constituents of an electron have any role to play in this? Suppose the edge (boundary) of a photon approaches the edge (boundary) of an electron ( this image is just for convenience). What happens next? Does some kind of attraction develop...

Continuous absorption spectrum -- why this happens? Homework Statement A pure green glass plate placed in the path of light, absorbs everything everything except green, similarly red glass plate absorbs everything except red. Homework Equations May i know the reason for this? Thanks...

Homework Statement While dealing with continuous absorption spectrum, my book depicts like this " A pure green glass plate when placed in the path of white light, absorbs everything except green and gives continuous absorption spectrum" Homework Equations The Attempt at a Solution...

This is my understanding; please, correct me if I'm wrong. If you bombard an atom with em-waves they will never break loose electrons until a certain threshold frequency. At this point the intensity of the light (or the amount of photons) striking the atom is proportional to the number of...

Hi, I'm hoping someone can advise me on the best place to find the absorption spectra for water (fresh) and ice, for the wavelength range UV to IR. Also, I'm looking for the solar radiation spectrum at the surface of the Earth (i.e. after atmospheric effects have been taken into account)...

What is meant when it is said that an electron emits or absorbs a photon (leaving aside the aspect of heightened or reduced energy states and orbit changes, which I understand.) ? I see four possibilities: 1. Whether the electron is a particle or a wave or some combination of the two, the...

Hello all, I come from musical sciences, but I'm trying to learn something about acoustics, so here I am, asking for some help about the impedance tube sound absorption coefficient test. I have and impedance tube, two microphones technique (ISO 10534-2), B&K microphones connected to the...

A layman with an interest in quantum mechanics here. Just want to check I understand something... Is the phenomenon of electromagnetic waves being emitted by an atom due to it being hot (black body radiation) different to that of such waves being emitted as a result of absorbing light...

I posted this http://answers.yahoo.com/question/index;_ylt=AioiPKUALWyrKuH4dGXejba9DH1G;_ylv=3?qid=20110618143816AAgRMyF"on Yahoo Answers yesterday, but it might be too specialized: If I understand correctly, the Cosmic Microwave Background Radiation is a perfect thermal (black-body)...

Hi there, I joined specifically to ask for help in exploring the possibility of harvesting the waste heat from a cars engine and recycling this energy to improve the engines efficiency. I'm assuming most people know about thermo dynamics, internal combustion and volumetric efficiency I:-p...

I'm going to be very careful to avoid the word "greenhouse" because of the indefinite ban on discussions about climate change - I want to be clear, this isn't a topic about that. Part 1 - some gasses in the atmosphere absorb and emit radiation in the thermal infrared range. Gases like water...

I know about the typical case of Paladium, which is said to "absorb 900x its volume in hydrogen". But this is completely vague. I'd like to know more about the theory of absorption as well as of other materials, like Nickel, Niobium and other transitional metals. Would someone, please, give me...

Does the absorption cross section to scattering cross section ratio of an isotope vary with neutron energy or stay constant? I have heard that cross sections in general are inversely proportional to velocity (eg the fission cross section of U235 is about 1000 times higher for thermal neutrons...

I keep reading that when a U-238 atom absorbs a neutron it turns into Pu-239. How does that happen? If I'm not mistaken Pu-239 is U-238 plus 2 protons and 2 electrons and minus 2 neutrons. When U-238 absorbs the neutron and becomes U-239 I can see that it can turn into Pu-239 if 2 neutrons decay...

I've been looking everywhere for information on the absorption spectra of molecular hydrogen. I need some pretty exact numbers. If anybody can point me in the right direction it would be greatly appreciated.

What is “undamped vibration absorption” ? What is “undamped vibration absorption” and how would you use this concept to absorb the vibration of a un-damped, simple mass spring system of mass m and stiffness k oscillating at its resonance frequency?

Lets take this specific example: Sun is radiating heat and a water tank with a certain surface area S absorbs this heat. Sun rays are perpendicular to this tank. [PLAIN]http://pokit.etf.ba/get/778c2978a453178481d142a891ae07c5.jpg If I know much energy did my tank of water...

so just about finishing a report on x ray abosprtion on different materials, generally the linear attneuation coefficent increases with atominc number Z. However silver(47) had a lower attenuation coefficent then zirconium(40) despite having the significantly higher value of Z. With some...

Homework Statement Complete this sentence. When doing Bragg scattering of x-rays off of NaCl, the first order K-Alpha peak has an energy that is ___________ the energy of the second order K-Alpha peak. Known Information It is known that the Intensity of the K-Alpha is greater than the K-Beta...

Hi, could someone tell me how the fine edge structure next the the absorbing edge in an XAS arises? from my understanding an XAS is a plot of absorption coefficient against energy of incoming xray. The absorption edge is at an energy corresponding to when the energy is just sufficient to...

Hello all. I'm am a first time poster but a long time visitor. I am having a little trouble that I was hoping someone far wiser and more knowledgeable than myself might be able to help with. I've been using MCNP to investigate criticality in a simple geometry consisting of a central natural...

I'm confused about infrared spectroscopy. Wikipedia states that "when the frequency of the IR is the same as the vibrational frequency of a bond, absorption occurs." However, if I look at some vibrational transitions of HCl for the anharmonic oscillator, I see: 0-->1 \omega = 2885.7...

Hey, It seems like this is impossible because momentum conservation is violated. I had a Q where an electron underwent an energy transition and emitted a photon, and then they asked whether it was possible for the photon to be reabsorbed by the electron to undergo the same transition as...

Looking at a HCl spectrum (from hyerphysics: http://hyperphysics.phy-astr.gsu.edu/hbase/molecule/vibrot.html), I don't understand why there is a gap in the middle of the spectrum that seems to act as a line of symmetry in the x-axis. Can anyone help please?

Homework Statement 1. When an aircraft flies above the clouds during the daylight period it is continuously exposed to sunlight. This sunlight heats up the cabin. Although the outside air temperature at cruise altitude is – 56 degrees this is still one of the determining factors for the sizing...

hi, this might be the wronge place to post this but trying to find this info on the web is exceedingly dificult. I need a material that is cheap has a heat insulating effect and has high transparency and permeability for al forms of the light spec rum including uv and infared. That is part...

Hi, i am doing a project course in masters. i need help regarding on X-ray Spectrum absorption by semiconductors. I am doing the simulations in XOP(X-ray oriented programs) software which is freeware at http://www.esrf.eu/UsersAndScience/Experiments/TBS/SciSoft/xop2.3 . So, my doubt is...

When white radiation is passed through a sample of hydrogen gas(atoms assumed actually) why are absorption lines observed in Lyman series only? The corresponding photon energy range for visible light(380-780nm) are 1.59-3.27eV which should cause transitions of electrons in the first excited...

Hey I recently did an experiment on the absorption of gamma rays I calculated the thickness and the no. of counts, got a nice exponential curve. So, I used lead as the absorbent or shielding material for gamma... Any suggestions what else I can use for gamma? I thought about sausages or...

Hi there! I have a question about the classical interaction of light with matter according the Drude-Lorentz model. Let's suppose that the light in matter has a wave-number k which in general is complex. Then the real part of k accounts for the propagation of light, while the imaginary part of...

Homework Statement Just basically want to see if my algebra is ok. Homework Equations All are relevent. The Attempt at a Solution Calculating Rates in Magnetic Moments to Predict Period Interaction Between a Fermion and the Zero-Point Field First we must identify the net...

I'm looking in a textbook at a discussion of a semiconductor quantum well which is being irradiated and an absorption spectrum produced. Electrons are being promoted across the band gap and holes are being created. There are heavy hole and light hole transitions, and the spectrum shown rises in...

Homework Statement 1.if you were to paint a house that reflects heat during summer and radiates heat during winter nights. which color should a house be painted? green, red, black, white, or pink? 2. why do gardeners mix soot in the soil? The Attempt at a Solution 1.i say it is...

Is there difference in absorption rate between various berries and fruits due to a place where you and your ancestors have lived? What I meant, is it true that my organism will absorb vitamin C much better from black currant than from lemon or kiwi (because I live in Baltic states and black...

I'm sure I'm overlooking something simple here. I am trying to understand characteristic x-rays given off during photoelectric absorption of a photon. The energy from the photon is given to an inner orbital electron and the photon no longer exists. The electron uses the energy to escape, and...