Spectrum Definition and 765 Threads

This is a question about the proper form for thermal noise from a resistor. This is purely academic for me - I always work in the regime where \hbar \omega << k T so the noise spectrum is simply P \approx kT. When this no longer holds, quantum effects matter of course. Then I have seen...

From what I've learned in physics, electrons falling from higher energy levels to a lower energy level emits an photon equal to that of the difference in energy between the two levels. Each atom has a set number of energy levels for the electrons, and thus each element can only emit a set number...

I have an unidentified radiation source. I used a NaI(Tl) detector and multichannel analyzer to collect data and plotted the spectrum. I found peaks at energies of 86.3, 123.7, and 369.6 keV. From this data I am attempting to identify the source, but I am having a difficult time. I tried using...

Hi there, it sounds like you are trying to analyze the behavior of a signal using MATLAB. It can be difficult to determine the exact behavior without knowing the equation, but here are a few things you can try: 1. Look at the autocorrelation function of your signal. This can give you an idea of...

on a visible spectrum scale what are the numbers for the colors of ROYGBIV? for example is violet 400-500nm and red is 700-800nm? how about the other colors? If the energy of a photon is 2.63 x 10^-19 J, how can we tell what color this is? i was looking at this electromagnetic spectrum and it...

Consider an unbounded self-adjoint operator defined in a hilbert space(its domain isn't the entire hilbert space,of course).Can its spectrum have discrete and continuous parts simultaneity?Does it have eigenvectors with finite norm? Thanks

Homework Statement I need to explain DSSS in my applied mathematics project (duration is three minutes of my talk). How do two users agree on which channel and the time to listen to so that they can exchange messages? Homework Equations Use Barker sequence as a channel encoder and...

Homework Statement A sensor yields a signal y(t) = |sin(120\pit)| a. Using Fourier analysis please construct an amplitude spectrum for this signal. Homework Equations A0 = \frac{1}{T}\int ^{-T/2}_{T/2}y(t) dt An =\frac{2}{T}\int^{-T/2}_{T/2}y(t)cos\frac{2n\pi t}{T}dt The Attempt at...

How can discreet quanta of photon energy make up a continuous electromagnetic spectrum, whose wavelengths are any arbitrary value? Is there overlap of quanta, temperature dependency, or so many finely divided energy levels that the spectrum just appears continuous? Electron energies are...

State space of QFT,CCR and quantization,spectrum of a field operator? In the canonical quantization of fields, CCR is postulated as (for scalar boson field ): [ϕ(x),π(y)]=iδ(x−y) ------ (1) in analogy with the ordinary QM commutation relation...

When we see the black body radiation graphic (intensity vs frequency), we could say the spectrum emitted by a black body is not discrete, it's continuous (as all the frequencies are emitted). How can this be possible? If we have a black body made of Sodium, wouldn't the spectrum have only...

I am a trainee science (specialising in physics) teacher. I upset my mentor a little bit by saying to a year 10 science class that there is "light" that people cannot see... by which I was referring to wavelengths of EM radiation that lie outside of the 400-700nm range. After the lesson, my...

Does anyone know where I can find a spreadsheet for the spectrum of an incandescent bulb?

1. Explain in fragmented way 1-methylstyrene's spectrum 2. Explain the gaseous and solid state PCl5 from IR and Raman spectra. Any help related to these two questions i would be happy, i want to study all about these 2 questions.Material(text,texbook) or explanation,anything.

Deuterium Spectrum (nm) 410.07, 433.93, 486.01, 656.11 I came upon these figures on a commercial product site for Deuterium lamps. So, question: Are they correct? If so, then... 364.5068222*(3^2/(3^2 - 4)) = 656.11 364.5068222*(4^2/(4^2 - 4)) = 486.01 364.5068222*(5^2/(5^2 - 4)) = 433.93...

Homework Statement Homework Equations a(+) = (-ip+mwx)/(2hmw)^1/2 a() = (+ip+mwx)/(2hmw)^1/2 The Attempt at a Solution can i use these operators to solve this problem? please help me i need to give this homework tomorrow morning :confused:

At first let's take a look at the eigenvalue problem for the momentum operator in x-representation. -i \hbar \frac{d}{dx} \psi(x)=p \psi(x) \Rightarrow \psi_p(x)=C e^{{ipx}/{\hbar}} The orthogonality condition is: \langle p_i|p_j \rangle=C^2 \int_R e^{i(p_j-p_i)x/{\hbar}} dx=C^2...

Homework Statement Hello, I have implemented single spectrum analysis and independent component analysis against a time series (in this case the euro foreign exchange) as a smoothing indicator. The ssa algorithm I purchased from: Caterpillar-SSA - http://www.gistatgroup.com/cat/programs.html...

I have been scanning a physics book. See attachment. The diagram shows that a light bulb has a continuous spectrum while the hydrogen has discrete spectral lines. Since the filament in the bulb is tungsten, why doesn't the light bulb also have discrete spectral lines?

I have diagonalized a Hamiltonian matrix many times with a varying parameter (varying magnetic field). This gives me the eigenstates and eigenvalues of the matrix for the different field values. I now need to track the diabatic states through (avoided) level crossings of the eigenvalues...

Here's a question from my textbook: "Why do you not see a spectrum of colors when light passes through a flat pane of glass?" However I think that a spectrum of colors will be formed when light passes through a flat pane of glass. The colors will all be parallel to one another, unlike a prism...

Hello Forum, how is is possible for quantum dots to offer a wide, broadband absorption spectrum but still have a single distinct emission wavelength? How is that asymmetry possible? For example, I would think that if we can absorb, say, 4 wavelengths, we can also emit those say 4...

I had "posited" or proposed this idea to a professor of mine about building a device which could capture all forms of electromagnetic radiation with varying sized charged particles and a solution that was conductive. Another option is a type of electromagnetic fabric which is basically...

Homework Statement What wavelengths emitted from a hydrogen gas discharge tube are associated with transitions from higher levels down to the n = 1 level? [a] infrared [b] visible [c] mixture of infrared and visible [d] ultraviolet Homework Equations Equations: 1/λ =...

This is an observational exercise where I have to find several different light sources and observe their spectra through a diffraction grating, then record my observations. I need two sources of each (i.e. continuous, emission, absorption). Continuous and emission are fairly easy, but for the...

Hello all, I'm not all too familiar with the electromagnetic spectrum, nor generally with physics but there is something that keeps me up. I learned, and also read now everywhere that visible light (to humans) lies in the wavelength range of about 400-700 nm. No I have a science book here...

Homework Statement I have a number of problems, to be completed in the next day or so (!) that I am pretty stuck with where to begin. They involve calculating the spectra of various different linear operators. Homework Equations The first was: Let X be the space of complex-valued...

Hi, I have a singular Sturm-Liouville problem with LCNO end-points, but also one limit circle point in the interior of the interval. Suppose I take boundary conditions that get me a self-adjoint extension of the differential operator, does anyone know if that gives me a discrete spectrum...

Hello OK so I'm very new to electronics and I really need some clarification/guidance. I am using this integrating sphere which is basically just a glorified photodiode. I am going to be measuring the output photocurrent using the responsivity curve of the photodiode. The sphere also has...

Hello everybody, So for this wind monitoring project I'm getting data from a couple of 3d sonic anemometers, specifically 2 R.M.Young 81000. The data output is made digitally with a sampling frequency of 10Hz for periods of 10min. After all the pre-processing (coordinate rotation, trend...

Homework Statement A radioactive source which is known to emit gamma rays only at a single energy is placed in front of a gamma ray detector. The gamma ray pulse height spectrum shows three distinct pulse heights of 7.38,6.49 and 5.60 volts. What is the energy of the gamma ray? The Attempt...

Hi, I have a bunch of spectra which happen to show some sinusoidal baselines, like this: I would like to subtract these baselines somehow. Of course I can try to fit sinusoidals using for instance Matlab's lsqcurvefit, but it seems like I have to be very careful with my input guesses not to...

My question is: Why the energy levels for sodium are different from those for hydrogen even though sodium is described as a "hydrogen-like atom"? Here I have posted the energy diagrams for sodium, and hydrogen. So, I have noted that sodium has 11 protons, whereas the hydrogen has only 1...

The problem statement Sketch the Amp spectrum of the following... Additionally, for x3, sketch the phase spectrum... ( j is the imaginary number) x1(t) = cos(10pi*t) + cos(3pi*t) x2(t) = cos(10pi*t) + cos(5pi*t) - j*sin(10pi*t) x3(t) = cos(10pi*t + (pi/6)) + j*sin(10pi*t) The...

I read that bond vibrations are only IR active if they produce a change in dipole moment. I'm trying to visualise how this works with chromium hexacarbonyl: If I'm not mistaken, this compound has one significant IR absorption at around 1900 cm-1, which is a C-O stretching absorption. Is this...

Homework Statement What can we say about the evenness and oddness of the power spectrum (|F(s)|^{2}) if the input fuction is purely real, purely imaginary or complex? I know that a real function will give an even power spectrum. But I can't prove it! Homework Equations F(s) =...

Hi,Everyone! I have a question! We often say hydrogen atom spectrum. But in nature ,it exists in the form of molecular hydrogen. today, I read something about hydrogen atom spectrum experiment. In the experiment ,we use hydrogen lamp. The Hydrogen lamp is a long glass tube filled with Hydrogen...

All electromangtic radiation comes under one continuous spectrum. http://en.wikipedia.org/wiki/File:Electromagnetic-Spectrum.png Different wavelengths of this radiation has different properties which is very evident in real life. However the whole concept remains extremely mysterious to...

If a hydrogen spectrum tube is filled with H2 gas and powered on, why do online sources show the tube emitting the spectrum of atomic single H hydrogen (the spectrum defined by the Rydberg formula)? Why not the H2 spectrum? For example, here: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

we set limits by what we can measure; therefore, it is what we have. This is my general understanding. I think it extends at both ends and we haven't found the means to measure it as of current. what are we doing to expand the spectrum? my simple question.

Today i was heating a bowl of soup..the intensity of the flame of the gas stove was quite high.. i observed that the bowl got burnt and when it cooled down a bit, i observed a band of colours..blue was the most prominent..i noticed the presence of violet, yellow and orange too.. I wish to know...

will, Red, Green and blue lasers wen crossed create the spectrum we crossed ?? hia, if i get red, green and blue lasers, and cross them at one point, and change the intensity of each one accordingly, will at the point of where they cross, display different colours relevant to the mixture...

I know that pulsars have been discovered as radio sources. But ... where does the hypothetical black body spectrum of a neutron star peak? Does it emit more in radio or in X rays? Thank you

Hello all, I have a vector, let's say A, which has measured values of the Earth's magnetic field (and if it is relevant, two vectors X and Y with the coordinates of the point each value was measured). I need to calculate the amplitude, phase and energy spectrum using FFT in MATLAB X...

When an element is excited by some method, it emits electromagnetic radiations of definite wavelengths. The arrangement of these wavelengths in order of increasing wavelength is called emission spectrum of the element. (as per my book) But, the definition of absorption spectrum, I don't...

Homework Statement Find spectrum and eigenvalues of operator from L^2(-1,1) to L^2(-1,1) T(f)(t) = ∫(t+s)^2f(s)ds The integral is taken over [-1,1] 2. The attempt at a solution I have already proven that this operator is self-adjoint and compact. However, I have now idea how to find...

This topic is quite confusing.. In the first place, how can we classify for example all O class stars would be having the same spectrum with the same absorbtion lines... Secondly, i just need a clarification on what do these absorbtion line reprsent and upon that how can we decide whether a star...

I've been deep into this topic for a couple of days and it is becoming just more and more confusing. I am yet a beginner so i would like explanations to be detailed and easy. Moving directly, my doubt is.. We treat stars as black bodies which emit radiation... From where did the stars originally...

the problem is attached as an image. im having troubles with the question. I'm assuming this is an induction question? i can prove it for the basis step n=0. but I am having trouble as to what i have to do for n+1 (inductive step). any help or hints would be great!thanks

So, can one achieve similar SS effects by simply FM modulating the offending source or does it have to be some sort of complex dithering scenario? The problem is harmonic emissions that so far do not respond to any other treatment such as shielding or absorption. The design is generating the...