Emission Definition and 546 Threads

As we know, if we have a group of atoms at a moment N(t) in an exited state, it will exponentially decrease according to the relation: N(t)=N(0) exp(-At)=N(0) exp(-t/(tau)) Where A is the Einsteins constant for the spontaneos emission, In my book they defined tau in the relation I...

If the star ionizing an HII region suddenly doubled the radiation emitted, would that increase or decrease the temperature? I feel like the expansion of the region would cancel out the increased energy, but I don't know.

From what I hear Uranium miners are constantly under threat from radiation gas which is released from Uranium mines. What I learned before is that there are 3 types of radiation. Alpha (helium), Beta (electrons), and gamma (photons). What kind of radiation releases radon gas. If its not...

This semester I'll be doing a lab project using a radio telescope to map out 21cm neutral Hydrogen in the galaxy to make a nice big image of it. (First proper hands on experiment:smile: ). Anyway that's the basic idea of it but I'm hoping in it to try to find something more specific in it...

Homework Statement What values of n are involved in the transition that gives the rise to the emission of a 388-nm photon from hydrogen gas? Homework Equations n=? wavelength = 388nm=3.88x10^-7 m R=1.097x10^7 m^-1 E= hc/ wavelength The Attempt at a Solution E= hc/...

I solved a, but I couldn't figure out b... I've tried different combinations but nothing turned out correctly... Homework Statement The emission spectrum of an unknown substance contains lines with the wavelengths 172 nm, 194 nm , and 258 nm, all resulting from transitions to the ground...

Homework Statement Sorry if this is the wrong place, I'm new here but I've been given a little paper to write on electromagnetic radiation. I am having trouble finding what the necessary conditions are for the emission of EMR, and kind of don't understand what it's really asking me for...

QW Why does the emission from hot hydrogen atoms consist of the Lyman, Balmer and Paschen series but the absorption of cold hydrogen atoms consists of just the Lyman series? is it because the cold hydrogen atoms absorb characteristic frequencies and the lyman series involves transitions that...

I have a question which was found on my Pre-lab Q> State the equation that is used to determine the energy content of a packet of light of specific frequency. Tried googling it,but couldn't find the answer.

A flash of light is emitted at point O and is later reabsorbed at point P. In frame S, the line OP has a length l and makes an angle theta with the x axis. In a frame S' moving relative to S with a constant velocity v along the x axis: How much time tau' elapses between emission and absorption...

Simply put, does it ever change? That is, does the line spectrum of a particular element or compound ever change? I've been searching all over, but I'm getting different answers!

# It is said that atoms of elements of high atomic mass are unstable. So they emit alpha, beta or gamma rays. Suppose an atom emits alpha rays. The binding energy of alpha particle is about 27 MeV(million electron volt). It is said that as a result of this emission, the binding energy per...

Hi there. I'm new to this board so please excuse if this is misplaced, there seems to be too many places to choose from. While browsing my computer I found a little program I wrote when doing year 12 physics that was based on the textbook material about ionization energies. It recurssively...

Using data collected from a spectrometer, with a diffraction grating of 100 lines/mm, I have collected a set of data. From this I have calculated wavelengths for the 1st and 2nd order lines of the three brightest visible colors, which were Blue/Violet, Green, and Orange. To complete my lab I...

why doesn't 238U decay spontaneously by emitting a proton?

Is there anyway of manipulating the emission spectrum of something like a gas by pumping it with a specific input? An argon gas laser, for example, will have lots of emission lines. Is there anyway of singling out groups of those lines without changing the gas? I would imagine such a method...

I had done a temperature variation PL (4 to 200 K) on my samples. I have found out that there are three emission line in the PL spectra, namely free exciton (FE), exciton bound to neutral donors(DX) and an unknown peak (let's called it XX). As the temperature was increased from 4 K to 200 K...

why does the burning of different materials often produce flames of different colors? I know that various colors of flames are due to excitation...but how is that applied here? Kat

I'm looking forward to doing some photography projects indoors, but I'm having a hard time differing between sources of light around me. I suspect that the lighting system in my basement is not as bright as I suspect it to be. Thus, I came to the conclusion that the upstairs room was a lot...

I'm confused So the atoms becaome excited by absorbing energy, like from a hot flame, so this energy makes an electron (or is it all electrons) in the outer shell (or is it all the shells) move to a higher energy level and when the electron(s) return to its(their) ground state, they give off...

Hi Guys, I've read a couple random pieces on Biophoton emissions from DNA and was quite interested in the topic. There seem to be quite a few suggestions that this could be some form of inter cell communication system. Before I waste a lot of time reading the wrong material I was hoping...

If photons are emitted or absorbed when a pair or a collection of particles, that are or behave as dipoles, undergo oscillation by some driving force, are there any systems that do NOT use a single or collective dipole oscillation to emit or absorb a photon?

When a photon is emitted, where did it come from? Did something cause it to be created and then emitted, or was it inside something and then released? How's it work?

In positron emission, a proton is converted into a neutron, a positron, and a neutrino: p --> n + e + v this conversion occures only in a nucleus, because this process consumes energy (the neutron and positron have a higher mass than the proton). The energy needed is twice...

Why does neon have more spectral lines than helium? Is the atomic spectrum based on an element's electron configuration?

Say I have a spectrophotometer that has a grating monochromator. If I want to measure emission instead of absorption from a lamp, could I just remove the exit slit? By removing the exit slit, doesn't all of the light just hit the sample?

Hi, I went to my proff to ask for my master thesis, he told me that you yourself have to do the experimental set-up for EMISSION AND REFLECTION SPECTROSCOPY ,,,but I am not that experienxed, anybody knows is it an easy task or...?

any isolated macroscopic system, like a large group of atoms, always tends to reach a state that has the maxium entropy. if the electrons in this group of atoms are excited, they will give out their energy so that more degrees of freedom are activated, hence the entropy of the whole system...

i heard some breaking news about a gamma ray emission which is confusing some scientists. did anyone heard about it?

Does anyone have a website which explains how to calculate the solar neutrino emission per second using the energies given in the p-p chain? thanks

Can someone please explain why an excited electron in an atom decays to the ground state, if energy eigenstates are stationary states.

A radio station operates at a frequency of 103.7 MHz with a power output of 200 KW. Determine the rate of emission of quanta from the station. Well I know the frequency and the power. I know the number of photons a second = (Power * Area) / ( Plancks Constant * Speed of Light ) / Lambda...

Here I have a problem: A 232/92 Uranium nucleus emits an alpha particle with kinetic energy=5.32MeV. What is the final nucleus and what is the approximate mass(in units) of the final atom. I can write the equation for the reaction, this will give 4/2 He and 228/90 Th. If the alpha particle...

I'm really lost on these 3 questions. My physics teacher decided she was sick of thermodynamics and gave us this packet over material we haven't covered yet, but she expects us to get it without any problem. I'm really stuck on these: 1. Assume that sodium produces monochromatic light with a...

Three Interconnected Questions: 1. When an atom is excited by a visible photon (KE=1 eV), does the probability (radial) density increase for the valence electrons or not? 2. If the probability density has increased outward, then what normally causes the excited state to begin the process...

Thermionic Emission... Why exactly does thermionic emission happen? ie - Why does heating a metal cause electrons to be emitted? I know that it must be that the heat is giving the electrons enough energy to escape from their atoms but in what form is this? ie - I know that electrons can be...

Hey does anyone know of a site where I can get the wavelengths of the strong emission lines of standard compact flourescent bulbs? It's very similar to mercury emission lines, but not the same exactly.

A Fe (57) atom is in an excited state 14.4 keV above the ground state. The nucleus decays to the ground state with the emission of a gamm ray. What's the recoil speed of the nucleus? I'm not sure how to set this up. I thought a photon would have no mass, therefor no momentum. If so I...

Could you please give me some pages or materials about this AE ? Where can i find out some nice tutorials ? Thanks

when an excited electron emits a photon what happens to the EM field of the electron

Is the top speed of light emitted by something the velocity of the light emitter + lightspeed or just lightspeed?

I'm reading an astronomy textbook, and I'm not sure about some things. The textbook says the EM waves are caused by accelerating charges. I don't understand how this is. I'm not sure, but my memory and intuition tells me that only charges moving in a sinuosidal (can never spell it) manner...

Classically, a pulse of light emitted by an atom would be viewed as an electromagnetic wave radiating spherically symmetrically out from the atom. Quantum mechanically speaking, if say a hydrogen atom emits a single photon, does the photon's wavefunction spread out spherically, us having no idea...

Hi, I need images of absorption and emission spectra for sodium to be used in a physics student book. Thanks in advance Stanley

Physics...nature of emission of radiation from atoms Hi everyone i am a Yr 11 student studying physics and i recently got an assignment that consists of a question that i cannot find thouroughly on the internet...hopeing people of this forum can help me... my question is...

This may be a dumb question: What is it about radioactivity that caused them to name it "radioactive"? All I was taught was that radioactivity is an emission of gamma particles, beta particles, or alpha particles. I don't remember anything about radio wavelength photons.