Spectrum Definition and 725 Threads

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...

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...

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...

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...

As I understand it, there are these categories: radio microwave infrared light visible light ultraviolet light X-rays gamma rays It seems that microwaves are really just radio waves that happen to have a very short wavelength, with the distinction that radio & microwaves are waves...

Hi I have read the following online (http://tf.nist.gov/general/pdf/1819.pdf): "Regardless of the application, the basic goal of locking the frequency of a laser to a cavity is to reduce the frequency fluctuations between the laser and cavity. The noise spectrum of the laser’s frequency...

Wikipedia showed me the solar spectrum during the day: http://en.wikipedia.org/wiki/File:Solar_Spectrum.png I imagine its very different at night, however is everything 0? Is there any residual black body infrared radiation?

Hello! I am doing a thesis in ecology using a two dimensional binary cellular automata. I have sampled a parameter for a number of generations and I would like to calculate the power spectrum for this data. I had been planning to use a software for this, but now it seems I have to do it...

Hello everybody, (sorry for the eventual Engrish) I can't find any convincing answer for the following question : Why do we always (or often) plot the CMB power spectrum in this way : jb.man.ac.uk/research/cosmos/vsa/images/CMB_power_spectrum.gif I mean the y-axis is $$C_\ell \ell...

A gas of a hypothetical atom in ground state (-14eV) is irradiated with photons having a continuous range of energies between 7 and 10 electron-volts. Photons of which energies will be emitted from the gas?The energy levels look like this: 0-------------------(ionization state)...

Does anyone know the difference between the power spectrum of a signal and the power spectral density (PSD) spectrum of a signal? I've read on the net lots of things ranging from: i) They are identical ii) Power spectrum is units of Watts, power spectral density spectrum units of Watts/Hz...

Would like to see if I've understood this question somewhat. :-) Homework Statement A doubly ionised Lithium atom (Li^++) has two of its normal complement of electrons removed. The energy levels of the remaining single electron ion are closely related to those of the neutral Hydrogen...

I know that an AM Amplitude vs. Frequency Spectrum has a central frequency = carrier frequency and two side bands of carrier frequency ± signal frequency. Now what would a similar spectrum look like for an FM wave ? My textbook just says that '... further side frequencies that are...

I was working on calibrating some newly purchased software onto our lab computers when I noticed that the decay spectrum on the screen did not look exactly as it does on published material. I attribute this to background radiation effects (correct me if I am wrong please), so I decided the best...

Could anybody explain what "power spectrum" in cosmology means. I am trying to understand the WMAP power spectrum graph, in particular. For example, what do the multiple moments physically represent? The graph is here: http://casa.colorado.edu/~ajsh/cosmo_04/wmapcl.html

What is the source of sunlight? The answer is Solar spectrum. Can anyone explain how the crimson color is created? actually what happen when the sunlight is created? Need help from the expert.

If A is a bounded operator on a Hilbert space H, isn't the following true of the residual spectrum \sigma_r(A): \lambda \in \sigma_r(A) iff (\forall \psi \in H, \psi \neq 0)((\lambda - A) \psi \neq 0) iff \ker (\lambda - A) = \{0\} iff \lambda - A is injective? So isn't the condition that...