Spectrum Definition and 765 Threads

Hi to everyone.. I am just reading an artical abouts FHSS... as it describes the frequency hoping adds security to the system cause u must know the algorithm for the frequency changes:) Unfortunately the article doesn't mention if this algorithm is transmitted at the start of the conversasion...

# A continuous band of radiation having all wavelengths from about 1000 Angstrom to 10000 Angstrom is passed through a gas of monoatomic hydrogen. In the emission spectrum one can observe the entire: a)Lyman series b)Balmer series c)Paschen series d)Pfund series I just don't have any idea...

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...

For any given velocity distribution, you have a y-axis with probability and an x-axis of velocity. Without really thinking much about it, I had assumed the normalisation condition was that the area under the graph (the integral of the function w.r.t. velocity) would be equal to 1. Of course...

Hello, In our day to day life, we see objects from distance in same shape and colour. Sunlight also reaches to us in somewhat same spectrum as it is emitted from sun. As such, why spectrum, interfered by atmosphere, is not changed or distorted--normally? Whether emitted, reflected or...

I was wondering if there is upper and lower limit (absolute) of frequencies for electromagnetic waves? My reasoning was as follows: the lower limit is bound by close to 0 Kelvin temperature of emitter and the upper limit of possible frequency for EM wave is by "planck's time" by relationship...

Hello, I've got some questions about an experiment I did about the spectrum of a x-ray beam which I measured by looking at the diffraction off a NaCl crystal of the beam coming from a tungsten anode as a function of the scattering angle. The measurement I got was something like the following...

Fourier transform --> power spectrum Hey all! I've been learning about the discrete Fourier transform (and FFT too) recently. What I don't understand is why applying it to a signal gives its power spectrum. I am not really good in physics, so to me it just seems like a magical formulae, one...

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 need help identifying this compound. I already know at 3000cm-1 and less than 3500cm-1 its a C -H. Less then 3000cm-1 must be of C-H alkane. Thats pretty much all I have identify. What I really need help is identifying the rest andnaming the compound. Any help would be appericated.

If a is in a Banach algebra (with identity 1) then the spectrum of a is a set consisting of \lambda \in \mathbb{C} such that (a-\lambda 1) is not invertible. That is, there does not exist (a-\lambda 1)^{-1} \in A such that (a-\lambda 1)^{-1} (a-\lambda) = (a-\lambda)(a-\lambda 1)^{-1} \neq 1...

need to hand in an assingment in an hour. would appreciate help on this : "Does the light emitted by a neon sign constitute a continuous spectrum or only a few colors? Defend your answer" thank you

3. Identify the Electromagnetic Spectrum range utilised in modern communication technologies. You must include secondary data in tabular and/or graphical form, interpret it into words and analyse. What kind of tables or graphs would I want to show here?

i'm having fierce trouble trying to obtain information as to the peaks/bonds in the IR spectra of the following; benzaldehyde, cinnamaldehyde, benzophenone, cyclohexanone and acetophenone. i keep typing in plenty of the keywords in the various search engines but to no avail. all i need is...

I need to show the splitting of the H_{\alpha} line of the Balmer series of a Hydrogen atom using the spin hypothesis. Here is my work on this. H_{\alpha} is obtained from the transition of the electron from the third orbit to the second i.e. from n=3 to n=2. Seletion rule for Hydrogen atom...

I'm trying to write an algorithm to identify peaks in various UV/vis spectra (as opposed to measuring them myself). I've seen software which does this - for example an FT-IR spectrometer here has software which goes through and does exactly this, labelling the wavelengths of everything. It's a...

A laser in visible is used in Raman spectroscopy and the resultant spectrum is in IR and Microwave region(which means molecular vibrations and rotations are excited), what type of interaction is this that induces these levels? ( I cannot think more than..."To be Raman active molecules should...

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...

Hello, Am I correct in thinking that the sublevels of an atom dictate its absorbtion spectrum? Also why is that a compound can absorb the same spectrum at every point, rather than individual atoms absorbing their respective spectrums? Thanks, -Scott

could someone explain this paragraph taken from "concepts of modern physics" by arthur beiser pg175? I'm having trouble understanding it... "A dynamical variable G may not be quantized. In this case, measurements of G made on a number of identical systems will not yield a unique result but...

If we look at any spectrum the lines are due to the corresponding transitions in sample. And the line widths are due to the uncertainity principle and doppler effect etc, if these effects are absent should these lines be just spikes?

what is deffrence between nutron energy spectrum and nutron flux

Theres the question presented to me. Now in all my wonderful glory, I enter "8" and boom, I am wrong. Just to be sure... i do 6, 7, 8, 9, and 10. None of them work. Then i start thinking... ok it can transfer from n=9 to n=8 to n=3 to n=1... but then that brings up an incredible number of...

I understand that there are atomic spectra for the elements, but how do you predict the line spectrum of a mixture of 2 elements like a H-He mixture? Must you combine the lines from both elements? Thanks.

Interesting post here http://motls.blogspot.com/2005/10/heterotic-mssm.html#comments It seems that a group of researchers has constructed a Calabi-Yau compactification that reproduces that particles of the standard model. The also obtain the SO(10) GUT group, and seem to get rid of some of...

phi(t)=A_o*e^(2*pi*i*mu_0*t) (label:1) Calculate the power spectra of the following waveforms (using 1): 1) for all t 2) a pulse duration of two tau for |t|<tau, and for phi(t)=0 --- 3)an exponentially decaying sinusoid: phi(t)=A_0*(e^(-t/(2*tau)))*e^(2*pi*i*mu_0*t) for t>0 and...

Would the power spectrum of the CMB tell you whether the cosmological principle is correct? Ack, I was going to try to explain my reasoning, but it doesn't really count as reasoning. :redface: I guess I was wondering what the CMB power spectrum tells you. If it's complicated, nevermind; I'm...

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, How can I prove that gravitational redshift preserves the characteristic shape of a blackbody spectrum?

i read a book and it mentioned energy spectrum of "typical" beta-minus decay. Look at the attachment. is this correct/sensible? i thought it should look more like a normal distributed curve. tell me if the book is wrong. thanks.

I have always visualized light as a series of discrete packages of energy. It seems fairly straight forward...at least until goes into more detail, but the smooth transition into a radio wave leaves me confused. Is there some specific point at which a radio wave becomes contiguous?

We see red to violet but how much further does it actually extend? I suppose it comes down to (1) the wavelengths of light not strongly absorbed by the atmosphere and (2) the limits on a water drop sufficiently refracting the longer/shorter wavelengths. Is the invisible portion of a rainbow...

ok I am asking this for a friend, but anyway: light consists of 7 basic colors (ROYGBIV) the question is quite simply why 7? why isn't brown in the spectrum? (note i tried to explain that brown is a combo of the other wavelengths but apparently the question is more like *why* is it only...

Hey this may be a stupid question but here goes... If you're underwater, say in a pool or something, and someone shines a light into the water will you see a color change? Why or why not?

The signal is from a voltage supply. I see lots of pages on the internet about this, such as this one, which shows what the magnitude spectrum looks like for a square wave with an arbitrary number of co-efficients. But how would I actually create that graph myself?

I have confidence that the moderators can correct my choice of forum if a mistake was committed. Although I do believe that this is the correct forum. I start this thread not because I know much about the Near Infrared (or NIR) spectrum but because I am of great need to know. Research in...

Hi all ! There is a question I can't find an appropriate answer. Conceptually, I can see what is ASE (amplified spontaneous emission) in lasers such as fiber lasers, but... what information does a measurement of the ASE spectrum give to us ? I know that reducing the ASE is of great...

I have a question about the spectrum of particles predicted in string theory. Assuming I have this correct here goes. If I look only at open strings I can predict the particle spectrum and I can get scalars, vectors, spinors, maybe spin 3/2, but no spin 2 particles. We can then look at the...

If the Sun is 98.4 % Hydrogen and Helium by mass, and 99.8% by number of atoms, why does it radiate a continuous spectrum of light? Why doesn't it radiate a bright emission line spectrum only at the Hydrogen alpha, beta, gamma, etc. lines plus the Helium lines, and little or no lines at...

I am working on a project for my electrical engineering lab class, and am interested in learning how to build a led spectrum display. I'm looking at very basic. I want 3 sets of LEDs, one for the high, one for the mid-range, and then one more for the low. Any clues where i can find a design...

Hello, all I have just read some foundamental concepts about EM spectrum in astronomy. One thing I don't quite understand is that "Stars with higher temperature or higher pressure shows a broadened line on its absorption spectrum". A brief explanation states that a higher temperature or...

is the color spectrum simply a small segment of the electromagnetic spectrum?

Hi all, I was wondering if someone could clarify what the difference is between a spectrum analyzer and a network analyzer. Thanks, Mike

Hi, this is a silly question Energy of a free particle is not quantized. Does it mean that it should have a continuous absorption spectrum?. When a cloud of free electrons in some type of plasmas is irradiated with light, theese "hot electrons" are accelerated as they absorb light. So...

In the 1969 edition of the World Book Encylopedia it shows that cosmic rays are considered part of the electromagnetic spectrum. In later editions the diagram doesn't show cosmic rays is part of the electromagnetic spectrum. In Capras famous book "The Tao of Physics, he also shows that cosmic...

... is the visible spectrum of light supposed to contain all the colors that we are able to see? if so, where is brown?

I am wondering just which parts of the EM spectrum can we and can we still not lase in. For the purpose of this thread, I consider the visible pretty much covered. But what about the IR, is there any thing between 3 and 10 microns? What is lasable at longer wavelengths? Are masers...

Hi, I am using matlab. I was wondering if anyone knew how to take the results from a spectrum analysis of a signal in x at sample frequency fs: y = abs(fft(x,fs)); and turn it back into the signal x. My purpose is to modify the spectrum by removing certain frequencies found in the spectrum...

Is there a frequency below radio waves or above gamma rays? What makes radio waves and gamma rays the bounds of the electromagnetic spectrum?

Hi...Juz curious. I was doing the prism experiment yesterday and was just curious about how the white ray of light changes to a spectrum of colours... Has it got anything to do with the change in the speed of the different colours of light, the frequency / the wavelength? Or just purely...