Spectrum Definition and 725 Threads

Hello all, I wanted to know what is meant by first momentum of energy spectrum (ES), second momentum of ES, and also third momentum of ES. It will be nice with some references, books, etc. thanks

Hello I am re-reading some of my old textbooks and have come across a simplified (non-relativistic) term used to correct the beta decay spectrum for the coulomb effect of the nucleus on the ejected beta particle. The expression is; F(Z,E) = (2*Pi*n) / (1 - exp(-2*Pi*n)) where n =...

A question about our vision Hi, I'm new here and this is the first time to post on this forum. I am really interested in physics and planning to major in mechanical engineer once I apply to colleges soon. However, I have a question that you people could either end the discussion quickly or...

Homework Statement This is from an old exam I'm studying from. It goes: "A particle of mass m is traveling in one dimension under the influence of a potential V = -Fx where F is a known constant. Find the energy spectrum and wavefunctions. Hint: You may want to work in momentum...

Can the absorption spectrum of an atom be shifted significantly using electric or magnetic fields ? such that to turn red to blue or something ? Another question, can atoms be excited to a certain energy level by applying external fields only with calculated energy ? thanks

Homework Statement Sketch and label the x-ray spectrum for an x-ray tube with copper as its target, operating at an excitation potential of 20kV.Assume that the copper energy levels are K shell=-9000ev,L shell=-1000ev,M shell=-200ev. Homework Equations This question has me a bit...

Hi, I tried sampling s(t)=sin(400\pi t) + 0.5cos(12000\pi t) at 10000Hz (below the Nyquist sampling rate) in MATLAB and plotted the spectrum, I found that it had frequencies at +-200Hz (same as the continuous signal version) and +- 4000Hz(instead of 6000Hz in the...

Homework Statement Hi, I need to find the spectrum of s(t)=sin(400\pi t) + 0.5cos(12000\pi t) when sampled at 10KHz.Homework Equations Using the Discrete Fourier Transform: G_{k}=\sum_{n=0}^{N-1}s_{n}e^{\frac{-j2\pi kn}{N}} where N is the amount of samples taken in the signal duration which...

About the intensity of x-ray emission spectrum of Molybdenum as a function of wavelength for various applied voltages: Explain fully: 1) the production of continuous radiation emitted 2) the absence of radiation of wavelength shorter than the minimum wavelength 3) the presence of the...

Homework Statement Hi, I need to find the spectrum of the following function: i=I_0[e^{\frac{-0.01(cos(2\pi 1000t)+cos(2\pi 100000t))}{0.026}}-1]Homework Equations the Fourier Transform would be: \int_{-\infty }^{\infty }I_0[e^{\frac{-0.01(cos(2\pi 1000t)+cos(2\pi...

Homework Statement The hydrogen spectrum contains a blue line with a wavelength of 434nm. Photons of blue light are emitted when hydrogen's electron drops from the fifth energy level to a lower energy level. What is the lower energy level? Homework Equations 1/wavelength = R [ 1/n2^2 -...

Hi all, I am confused with the amplitude at 1x, 2x, 3x frequency. The 1x, 2x and 3x is the harmonic (or mutiples) of the original frequency, meaning that if the shaft is turning at 1500rpm, then 2x will be the amplitude at 3000rpm and 3x will be the amplitude at 4500rpm right? But how will...

For some of my work, I am investigating methods of scanning for nuclear material. As part of my study, I have run across Gamma Ray Spectroscopy: http://en.wikipedia.org/wiki/Gamma_spectroscopy" What I am having trouble with is reading a gamma ray spectrum (I am a software engineer with a...

Hi, I'm trying to compare the spectrum of male and female voices using Matlab. I'm using this code but I get this error: --------------------------------- Warning: SPECTRUM is obsolete and will be removed in future versions. Use the spectrum objects instead, type "help SPECTRUM". > In spectrum...

Homework Statement How to show element of finite dimensional banach algebra has finite spectrum? Homework Equations spectrum(x) = set of complex numbers 'c' with cI-x not invertible, I is identity The Attempt at a Solution please help to start, I don't know

I am trying to graph the frequency spectrum of a signal over time. To do this, for each frequency I use a filter defined by the following equation: y_n = Ae^{i\omega_0}y_{n-1} + x_n This has a frequency response of \frac 1...

Homework Statement Light from a laboratory sodium lamp has two strong yellow components at 589.5923 nm and 588.9953 nm. How far apart in the first-order spectrum will these two lines be on a screen 1.00 m from a grating having 10,000 lines per centimeter? Homework Equations Grating...

Quick question from a complete science ignoramus. The electromagnetic spectrum is described as a continuum, correct? So, given the scales of frequencies that our science is familiar with, The high end would be gamma rays, with frequencies of 300 EHz, the low end being extremely low frequency...

Are all the frequencies of the Electromagnetic spectrum in a beam of light before being filtered by the Earth's ozone? Beyond ROYGBIV though.. so like infrared rays, microwaves, xrays, etc

Homework Statement When the ionized particles entering a mass spectrometer are simply accelerated across the potential difference between two charged plates, there is always the chance of an uncontrolled variation in their velocities due to their random thermal motion before they undergo...

Hi, all I've been reading these forums for a while, and now that I have a question, I've finally decided to join. The question I have is school-related, but not really direct coursework since it's very open-ended. I am part of a group (in electronics class) that is building an LED...

Question: A hydrogen atom has one electron. If we heat hydrogen gas up enough, we will completely separate each electron from each hydrogen atom (called "ionization"). What will the spectrum of ionized hydrogen look like ("ionized" means that the electron has already been taken away)? Here's...

Homework Statement The Attempt at a Solution The carrier wave is by inspection 0.5 + cos(10\pi*t) and the other would be 1.5*sin(60\pi*t). I'm not entirely sure what we're supposed to graph for the second part, the frequency spectrum. Any help?

Hello--- I am reading a paper which presents a method to determine attenuation (and Q factors) from reflection seismic data (Y. Wang, "Q analysis on reflection seismic data," Geophysical Research Letters, Vol. 31, 2004). To perform signal processing on a seismic trace, the paper describes...

I was just wondering if anyone knew of anywhere on the internet that had a list of all known emission spectrums of the elements. Thanks!

Sorry if this isn't the best forum for this question; putting it here due to a gut feeling cos my brain wouldn't tell me where to put it. I'm thinking of an idea for an art project. I'd like to somehow depict what a boring, every-day scene might look like if our eyes could see more of the EM...

Hi readers, I'm confused about some aspects of absorption spectroscopy, and hoping someone can de-confuse me First, just a preliminary question; am I right in thinking that when an electron absorbs a photon, the electron will then emit a photon of the same frequency and energy as the one...

Homework Statement Compute the solar irradiance in the near IR range (0.7 - 1.5 microns) at the top of the atmosphere over Denver at noon on August 23rd, and assume that 37 per cent of the solar spectrum is in this range. Homework Equations Equations? I=ScosZ where Z is the azimuth...

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?

There is a debate going on regarding this subject, and many different physics professors, who have a PhD in optical physics, are providing different answers. It looks like they are getting destroyed in the debate which is rather silly. I have been watching and I am very curious about the...

Hey, For my first post here, I had a question about the gamma spectrum of Na-22. I measured the gamma spectrum of Na-22 with a Ge-spectrometer. Using Genie-2000 software I saw two peaks in the spectrum, 1274 keV (peaksurface 3981±1,74%) and 511 keV (peaksurface 25494±0,68%). (Horizontal...

The question I have is a bit difficult to express. The foundation of my question. Within the electromagnetic spectrum there is the visible spectrum. Broken down that has our individual colors that we see. Do all portions of the electromagnetic spectrum have special properties such as...

Hi. I'm doing a lab where we hooked up an RF signal generator at 1.25MHz/10dBm to a spectrum analyzer using a 50 ohm wire. Can anyone explain to me or link me to a place where I can read about why a real sine wave's frequency spectrum is not a pulse? Also, why would with a sweep from 1 Mhz...

Hello, I have studied X-ray emission when an electron beam is fired at a tungsten target - But when I was presented with the graph of Intensity versus wavelength, I was confused... I saw a curve, and on it there were spikes. What are these spikes, and why are they caused? Something to...

Hi, I have a question concerning a hydrogen spectrum: There are 4 energy levels drawn: Starting from the top -1.4 * 10^-19 Joules -2.4 * 10^-19 Joules -5.4 * 10^-19 Joules -21.8 * 10^19 Joules 1st question: Going from the second level to the third from the top (from -2.4 to...

Why distances between lines of hydrogen spectrum decreases even though the distance between the shells of Hydrogen increases as we go to higher shells? r=Ɛn2h2/πme where m=mass of electron, e=charge on electron h=planck's constant n=principle quantum number r=radius of hydrogen atom...

Hi, For my experiment, i need the gamma ray energy spectrum of Cd-109 and Sn-113 with NaI detector. would anyone help me please? thanks everyone.

Hi. What I'm trying to do is to obtain the energy spectrum from the following dispersion relation: E^4-A·E^3+B·E^2-C·E+D-F·E^2·cos(k·a_0)^2+G·E·cos(k·a_0)^2-H·cos(k·a_0)^2 = 0 where E is the energy, k is the wave vector and a0 the distance between adjacent neighbors in a 1-Dimensional...

cause of spectra is transition of electron form one state to another state. but which one? emission spectra or absorption spectra. or in what case both spectra can be seen?

Hey can someone explain the significants of the different components of the Compton spectrum? I know that the Compton edge comes from the incident angle of the photon approaching 180 degrees and that its the maximum energy that can be transferred from the photon to the electron without reaching...

Homework Statement Let X=C[0,\pi]. Define T:\mathcal{D}(T) \to X, Tx = x" where \mathcal{D}(T) = \{ x \in X | x(0)=x(\pi)=0 \}. Show that \sigma(T) is not compact. Homework Equations None. The Attempt at a Solution Well, functions sin(Ax) and sin(-Ax), for A=0,1,2,... are in the domain...

Difference between two rotational terms is given by \tilde{\nu}=(J+1)(J+2)B-J(J+1)B=2B(J+1) If we put values of J in this expression we get that otational spectrum is equidistant. T_r - rotational term J - rotational quantum number But from this picture spectrum isn't equidistant...

the question states that the emission spectrum of hydrogen contains a line with wavelength 656.2nm. and we need to approx find out what temp the H gas needs to have to be heated before this line appers in the spectrum i have worked out that for this wavelength the electron mov from level 3 to...

Homework Statement Assume that the limits of the visible spectrum are arbitrarily chosen as 430 and 680 nm. Calculate the number of rulings per millimeter of a grating that will spread the first-order spectrum through an angle of 20.0 degrees. Homework Equations (y is lambda) dsinø =...

Hello, Does anybody know if there has ever been an emission spectrum of Earth recorded by one of our spacecraft s after launch from outer space? When we directly image extrasolar planets we are able to determine their atmospheric properties, etc, so can someone point me to a link which...

You can know the temperature of a star by fitting a black body spectrum. BUt what if the star is moving with some radial velocity v? I worked out that: I(\lambda_0,T)=\frac{8\pi h c}{\lambda_0^5}\frac{1}{e^{\frac{hc}{\lambda_0kT}}-1}...

Homework Statement Here is the question: how can we know that if we have discrete or continuous spectrum just by looking at the potential graph? Specifically, let`s consider the potential V(x)=-F*x (F:const) . After we solve, we can conclude wavefunctin is airy function, and so both...

NMR NOESY spectrum -- Please help! "trans-9-(2-phenylethenyl) anthracene" Here is the NOESY spectrum: http://img109.imageshack.us/img109/5708/wittiggosy.jpg Here is the Proton NMR and the structure of the molecule: http://img40.imageshack.us/img40/1774/wittigprotont.jpg )...

Hi all! It's my first post, but I follow this forum since a couple of years. Now I have a big question for you: how to measure the CDM (or \LambdaCDM) power spectrum (better, the variance \propto k^3 P(k)) from the observations? What parameters are necessary?

DOS of metallic CNT Hi all, I am in doubt on a subject. The density of states function of a metallic CNT, is given as http://img196.imageshack.us/img196/5629/adszuci.jpg in the book "Introduction to Nanoelectronics" of Hanson. On the other hand, in the same book, it is said that...