Spectrum Definition and 765 Threads

In his article on the Zero-point Energy: http://www.calphysics.org/zpe.html Bernard Haisch says: That the spectrum of zero-point radiation has a frequency-cubed dependence is of great significance. That is the only kind of spectrum that has the property of being Lorentz invariant. The...

Homework Statement The outermost electron in a sodium atom can be in these energy states: (1)-0.82 aJ, (2) -0,48 aJ, (3) -0.31 aJ 1 aJ= 10^{-18} J. When we study the spectrum of a sodium lamp, we see a yellow line. Use the above given energy states to determine the wavelength of this yellow...

I mean how can i analysis the thermal conductivity of two structures with their phonon spectrum. thank you!

I have been posting on here pretty frequently; please forgive me. I have an exam coming up in functional analysis in a little over a week, and my professor is (conveniently) out of town. We proved in our class notes that if T:X\to X is a compact operator defined on a Banach space X, \lambda...

i and my friend want to have spectrum of star. i need star light with high intensity to diffract this. unfortunately, we don't know how we can have a intense light? do you know how we can do this? or in general, how can we have spectrum of light star?

hi everyone, i would be grateful for suggestions for the following problem: i have a set of measurements, discrete samples from a continuous function of time. with each measurement comes a estimate of its uncertainty (standard error). by doing a discrete Fourier transform, i have seen some...

What are the conditions for which it can be concluded that a system has discrete energy levels? For example a system in one dimension with the potential V(x)=b|x| has only a discrete spectrum. How I can prove it? My book says moreover that the energy eigenvalues have to satisfy the...

no of line in line spectrum is equal to jumps of electron from one shell to another. Am i correct. IN my book it is written that if a electron in hydrogen jumps from n1 to n2 then number of spectral lines is given by formula {(n1-n2)(n1-n2+1}/2. so consider a electron jump from 4th shell to 2nd...

Our eyes have 3 types of cones to perceive color, one for red, one for green, and one for blue. On the one end of the spectrum we see red. But on the other end of the spectrum we do not see blue, but beyond blue we have violet. How is this possible? :confused: A bit of research found...

Hello, does anyone know of a code that will generate the expected neutron spectrum for an AmBe neutron source along with the expected reaction efficiency?

Hey all, I am trying to locate an atomic spectrum for the following elements. O2 and N2 I have the information from 10nm - Visible, but the internet seems to be always missing the first piece of information that is vital to my experiment. Thanks for any assistance in locating. I have...

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, I am new to QM, so advanced apologies for the dumb questions to follow. What does "the spectrum of boundstates is non-degenerate" mean? And why is the time-independent Schrodinger eqn reflection invariant? (I'm not sure I quite know what that means either...) Thanks!

Hi guys, this is a homework question, but i didnt think it belonged with the physics questions. I have the spectrum of a star, it has hydrogen gamma and hydrogen beta absorbtion lines, but a very very strong hydrogen alpha emission line. What is the significance of this, I would expect a...

If I modulate a pulse X(t) with a.) a sine wave or b.) a cosine wave, I have the frequency spectrum expressions a.) \frac{1}{2j}[X(f-f_0)-X(f+f_0)] b.) \frac{1}{2}[X(f-f_0)+X(f+f_0)] When I plot these for a pulse, I see a difference in the magnitude spectrum, but I should not expect...

Hi all, I'm working on Taylor's text on scattering (a reference from Peskin and Schroeder). They define the Moller operators \Omega which are isometric, satisfying \Omega^{\dagger}\Omega=1 This is not necessarily the same as unitary in an infinite dimensional space, the difference being...

My question is, when extracting the count rate from a particular peak in the energy dispersive spectrum (e.g. X-ray fluorescence) Is this done by simply drawing a straight horizontal line from the top of the peak to the y-axis and the corresponding intercept will be the count rate? What if the...

Hi all, I have 2 questions related to the blackbody spectrum. 1 - If a blackbody emits (and absorbs) energy at all wavelengths equally, why does the spectrum look the way it does (i.e. why does it peak in intensity at a given wavelength?) 2 - The fact that the cosmic background radiation...

Homework Statement Hydrogen atom with ionisation energy 13.6 eV is found to have an emission spectrum with lines at 1.89 eV, 10.20 eV and 12.09 eV. Draw a labelled diagram to show the energy levels of hydrogen atom by showing the transitions of electrons causing the emission of the lines...

Hello, I'v been taking an interest to astronomical spectroscopy lately and I have some questions about that. In order to get myself going I wanted to get as much information about Sirius A and Sirius B using the distance, obtained by using parallax(I didn't do that but imagine I did) , and...

Homework Statement What is the cause for the bump in the lower energies of this spectrum: http://en.wikipedia.org/wiki/File:Gammaspektrum_Uranerz.jpg The Attempt at a Solution Is it just normal Compton? I'm doubting that because that is very asymmetric. I can't find anything in any textbook I...

Homework Statement The question says for the hamiltonian \hat{}H+\hat{}H1 calculate the complete energy eigenvalue spectrum. for the ground state show that the result agrees with the one found by the perturbation theory previously. I'd assume \hat{}H here is just the standard...

Hello, I am working with python's Image Library (PIL), Sympy, and Matlab. I have a topographical map of the earth, ( see 3d warehouse from google ). I am wondering if with an rgb matrix from a jpeg heightmap is traditionally the value of black and white ignored, because it seems that the...

Hi, I'm looking for papers and general or specific information about the topic Astronomy in UV and X-ray Spectrum. Other than Wikipedia and Google sources, I would be interested in understanding the optical spectrum range and its limits, with respect to the materials used in this astronomy...

shining white light through a gas of a vapourised element causes absorbtion lines to be created in the white light spectrum ie. there are dark lines running through the otherwise continuous spectrum and the position of these lines are unique to particular element. Why is it though that we...

Homework Statement Not really a homework question, but related none the less. I'm confused about what exactly the amplitude spectrum is. As well as the power spectrum. Homework Equations Not really taking a purely mathematical approach here, I'm using numpy for python. Specifically the fft...

Hi guys, I am eager to find out about our spectrum usage. Cause I am working on LTE and it uses either 2.7 GHz or 900 MHz, range of UHF. Do anyone have a link, paper or book referring to various applications spectrum usage, like all other mobile communication or defense spectrum usage. Thank...

Homework Statement Today I did an experiment to met the light intensity, a function of the wavelength of light. I gained a theoretical model *how it should look*, which had 1 light intensity peak at lambda=1083nm. On the other hand, I measured several peaks, 1 at ~600nm and another at ~750...

If light is quantized, and is given out in packets, why are the EM wave spectrum and the black body spectrum continuous? I am very confused, can someone offer some explanation? Any input is greatly appreciated.

Hi! I am new to these, and off the bat am confused by the units. Manufacturers quote resolution either in units of length, e.g. 0.04 nm, or HZ. For example, 0.04 pm / 5MHz 0.16 pm / 20 MHz 0.8 pm / 100 MHz. I am thrown by this since I thought frequency was the inverse of...

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?

Can someone give a clear definition of what we mean when we say the CMb spectrum is adiabatic and what it means for simple infaltionary models?

i am trying to plot the amplitude spectrum for a function which has the following properties: f(t) = 1, 0 < t < 10 f(t) = 0, 10 < t < 20 the period of the function is 20 i found the Fourier coefficients to be Fn = -(1/n*pi)(cos(n*pi) - 1) i tried to use the following code to plot the...

I am a piano teacher with some very cool, science-minded students. Usually we stick to basic acoustics, and mechanics in terms of piano technique, but yesterday one of them took things in an interesting new direction. . . he described to me how, when he closes his eyes and listens to the music...

I was glad to see this paper for several reasons. The volume operator in Loop Gravity is the locus of some interesting unresolved questions. The kind that requires and attracts creative mathematicians IMHO. This first paper from Gene Bianchi and Hal Haggard is just a 4-page letter I guess for...

Hello, Over the past few weeks I've been interested in the idea of developing a celestial mass accretion spectrum, or in other words, a spectrum that places celestial objects of a given mass as being part of a band of that spectrum. This spectrum would help give definitions on what a planet is...

I have 3 questions: 1)Does the lines in the spectrum of a star indicate the elements in its surface or also the inner parts? 2)when an electron goes to a higher state, it emits a photon with a wavelenght according to that transition, and we can see that line in the spectrum of that star? But...

Hi there! I'm studying that if r is the quantum number associated with the total angular momentum of a diatomic homonuclear molecule, then only odd or even values are allowed for r. Now, the selection rules for r requires a change of one unity, but if my molecule has only odd values for r...

Homework Statement Write the volume element of d3p as a function of "nu". Assume spherical symmetry in doing this change of variables so write d3p = 4\pip2dp. Homework Equations n(\nu)=\frac{1}{e^{\frac{h \nu}{kT}} -1} \epsilon=\frac{2}{h^3}\int h \nu \cdot n(\nu)d^3p The Attempt...

Homework Statement In manipulating transmission spectrum data from GaAs and InP I'm told to "Look up the refractive indices of GaAs and InP in the region of  = 1.0 micron, and use these to correct your experimental data for reflective losses and plot the corrected transmission T’ in...

I have m(t)=0.2sin(w1*t) + 0.5cos(w2*t) ---> Note: the 1 and 2 besides "w" (omega) is not a coefficient, its a subscript to show that they are different. I found the Fourier transform to be M(F)=0.25[∂(f-f2)+∂(f+f2)] + 0.1j[∂(f+f1)-∂(f-f1)]. My question is, how do I sketch the magnitude...

This is a problem intended to show us that Astronomers are sometimes fooled into thinking that a cosmic source of radiation is thermal, when it is not. Here is the problem: Consider a cosmic source emitting one hundred solar luminosities all within 1 MHz of the single frequency of 22 GHz...

RAMAN spectrum of iron oxide ! Dear every one! I have just got a new raman spectrometer to study the corosion of metals. i tested it on liquids (alcool, benzene, solvant ...) it works very well. i did also experiments on coal and carbon, perfect ! but when i tested on iron oxide .. i got no...

Homework Statement For a downtime analysis the spectrum of motion has to be calculated with the wave spectrum and the RAOs (given) for several frequencies. Given is a wave scatter diagram with the significant wave height (Hs) and the peak period (Tp). How convert the significant wave height...

Homework Statement I'm trying to calculate the optimum band gap for a solar cell for an essay I'm writing, but I am missing a step somewhere along the way. A solar cell has an energy transition E. Any photons with incident energy hv<E are not absorbed. Any photon with energy hv>=E are...

Homework Statement Much as the title says, I need to construct an example of a linear operator on Hilbert space with empty spectrum. I can very easily construct an example with empty point-spectrum (e.g. the right-shift operator on l_2), but this has very far from empty spectrum. If I...

I have a spectrum analyzer and pulse generator. I decided to see what the spectrum of a sequence of pulses was and found some surprises. The pulses have very fast rise and fall times (5 nanoseconds) with a pulse width of 30 nanoseconds. As a result I obtained the classical (Sinx/x)^2 power...

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...

where can I get information about the excitation levels (gamma ray spectrum) of a single proton nucleus?

I wanted to know if there was a standard way of finding out the spectrum of a Hamiltionian given a specific H. For example, H = -\Delta - 10|x|^{3} + |x|^{4} or H = -\Delta -(1+|x|)^{-2}. I don't need answers to the above, I just want to know if one can describe the spectrums of...