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Electromagnetic radiation is introduced at the intro to article. In the body of article EMR is used for the concept on several places. When a novice reader is focused on a part of the body text and only skims the surroundings, EMR acronym's meaning might not be obvious, and search within page would not quickly bring full text to her or his attention.
I propose the change at first use to electromagnetic radiation (EMR)' in intro; if nobody opposes I'll do it in a day or two. Marjan Tomki SI ( talk) 14:05, 23 December 2022 (UTC)
To this mathematician, the meaning of the phrase "the variation in the intensity of electromagnetic waves with respect to their frequency or wavelength of oscillation" (as well as the earlier versions "range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies" and "ranging over a domain of frequencies and their respective wavelengths and photon energies") is close to incomprehensible. The version that I wrote made sense to me (well yes of course); the revert edit summary does not. (I also think "The electromagnetic spectrum is the spectrum of electromagnetic radiation" is so obviously tautological as to be pointless, but at least I understand what it says.) Would value input from other editors of this page. -- JBL ( talk) 17:43, 6 December 2023 (UTC)
which is defined asNo I don't think so -- that is one definition, but it's not the only (and outside of specialist contexts at least not the primary) definition. I mean just look at the lead sections of Spectrum (physical sciences) and Spectrum. -- JBL ( talk) 17:22, 9 December 2023 (UTC)
Objects in the universe send out an enormous range of electromagnetic radiation. Scientists call this range the electromagnetic spectrum, which they have divided into a number of categories.Or a chemistry textbook:
This figure also shows the electromagnetic spectrum, the range of all types of electromagnetic radiation.And a typical phrasing from later in the book:
Compare the two types of emission spectra: continuous spectrum of white light (top) and the line spectra of the light from excited sodium, hydrogen, calcium, and mercury atoms.Or, if you want a straight-up physics reference, Table 9.1 in Griffiths' Introduction to Electrodynamics is "The Electromagnetic Spectrum", and it lists frequencies, their corresponding wavelengths, and names where applicable: intervals, but not functions on those intervals. Problem 9.23 reads,
If you take the model in Ex. 4.1 at face value, what natural frequency do you get? Put in the actual numbers. Where in the electromagnetic spectrum does this lie, assuming the radius of the atom is 0.5 Å?The term "electromagnetic spectrum" is being used to refer to the interval, not any function on it. The Feynman Lectures on Physics use the term as follows:
The fact that we can see in a particular frequency range makes that part of the electromagnetic spectrum no more impressive than the other parts from a physicist’s standpoint, but from a human standpoint, of course, it is more interesting.And later:
This is the first of a number of chapters on the subject of electromagnetic radiation. Light, with which we see, is only one small part of a vast spectrum of the same kind of thing, the various parts of this spectrum being distinguished by different values of a certain quantity which varies.XOR'easter ( talk) 17:26, 9 December 2023 (UTC)
spectrum: representation of a real or complex quantity as a function of frequency. [1]
Note 1 to entry: Other quantities related to frequency are often used as variables, e.g. wavelength in vacuum or angular frequency.
Note 2 to entry: The word "spectrum" is also used to denote the frequency band where some phenomenon occurs, e.g. acoustic spectrum, visible spectrum.
power spectrum: the distribution as a function of frequency of the square of the amplitudes of the spectral components of a signal or noise. [2]
Note – The spectrum of an electromagnetic radiation, defined in chapter 845, can be considered as a power spectrum.
amplitude spectrum: the distribution as a function of frequency of the amplitude of the spectral components of a signal or noise, [3]
fgnievinski ( talk) 04:22, 12 December 2023 (UTC)phase spectrum: the distribution as a function of frequency of the initial phases of the spectral components of a signal or noise. [4]
Physics articles should focus on the physical phenomenon, not on the mathematics we use to describe it. The electromagnetic spectrum is not a function—that is a mathematical concept, not a physical one. It's not the domain either. I would rephrase what JBL wrote above this way: "The electromagnetic spectrum is the full range of electromagnetic radiation, from the lowest-frequency radio waves to the highest-frequency gamma rays." That gets us in the mindset of physics from the start and focuses on the topic itself, leaving the distraction of frequency vs wavelength vs photon energy for a subsequent sentence.-- Srleffler ( talk) 04:51, 12 December 2023 (UTC)
We should stick to the sources, especially secondary and tertiary sources, which give two clear meanings: EM spectral density and EM frequency domain.Except that they don't. The sources give one clear meaning for "electromagnetic spectrum" in its own right, and other clear meanings for other uses of the word "spectrum". XOR'easter ( talk) 15:44, 15 December 2023 (UTC)
Why didn't anyone notice the MIR and FIR values for Photon eV is reversed. Wrong numbers in the table. 65.36.54.181 ( talk) 13:01, 19 December 2023 (UTC)
I just stumbled upon the UV section: lots of "short wavelength" discussion. I encourage editors to avoid using "wavelength" in any sentence here about energy. Energy is proportional to frequency. Using the inversely proportional wavelength is unnecessarily confusing and physically not helpful. Johnjbarton ( talk) 21:30, 27 January 2024 (UTC)
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This
level-4 vital article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
This page has archives. Sections older than 360 days may be automatically archived by Lowercase sigmabot III when more than 2 sections are present. |
Electromagnetic radiation is introduced at the intro to article. In the body of article EMR is used for the concept on several places. When a novice reader is focused on a part of the body text and only skims the surroundings, EMR acronym's meaning might not be obvious, and search within page would not quickly bring full text to her or his attention.
I propose the change at first use to electromagnetic radiation (EMR)' in intro; if nobody opposes I'll do it in a day or two. Marjan Tomki SI ( talk) 14:05, 23 December 2022 (UTC)
To this mathematician, the meaning of the phrase "the variation in the intensity of electromagnetic waves with respect to their frequency or wavelength of oscillation" (as well as the earlier versions "range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies" and "ranging over a domain of frequencies and their respective wavelengths and photon energies") is close to incomprehensible. The version that I wrote made sense to me (well yes of course); the revert edit summary does not. (I also think "The electromagnetic spectrum is the spectrum of electromagnetic radiation" is so obviously tautological as to be pointless, but at least I understand what it says.) Would value input from other editors of this page. -- JBL ( talk) 17:43, 6 December 2023 (UTC)
which is defined asNo I don't think so -- that is one definition, but it's not the only (and outside of specialist contexts at least not the primary) definition. I mean just look at the lead sections of Spectrum (physical sciences) and Spectrum. -- JBL ( talk) 17:22, 9 December 2023 (UTC)
Objects in the universe send out an enormous range of electromagnetic radiation. Scientists call this range the electromagnetic spectrum, which they have divided into a number of categories.Or a chemistry textbook:
This figure also shows the electromagnetic spectrum, the range of all types of electromagnetic radiation.And a typical phrasing from later in the book:
Compare the two types of emission spectra: continuous spectrum of white light (top) and the line spectra of the light from excited sodium, hydrogen, calcium, and mercury atoms.Or, if you want a straight-up physics reference, Table 9.1 in Griffiths' Introduction to Electrodynamics is "The Electromagnetic Spectrum", and it lists frequencies, their corresponding wavelengths, and names where applicable: intervals, but not functions on those intervals. Problem 9.23 reads,
If you take the model in Ex. 4.1 at face value, what natural frequency do you get? Put in the actual numbers. Where in the electromagnetic spectrum does this lie, assuming the radius of the atom is 0.5 Å?The term "electromagnetic spectrum" is being used to refer to the interval, not any function on it. The Feynman Lectures on Physics use the term as follows:
The fact that we can see in a particular frequency range makes that part of the electromagnetic spectrum no more impressive than the other parts from a physicist’s standpoint, but from a human standpoint, of course, it is more interesting.And later:
This is the first of a number of chapters on the subject of electromagnetic radiation. Light, with which we see, is only one small part of a vast spectrum of the same kind of thing, the various parts of this spectrum being distinguished by different values of a certain quantity which varies.XOR'easter ( talk) 17:26, 9 December 2023 (UTC)
spectrum: representation of a real or complex quantity as a function of frequency. [1]
Note 1 to entry: Other quantities related to frequency are often used as variables, e.g. wavelength in vacuum or angular frequency.
Note 2 to entry: The word "spectrum" is also used to denote the frequency band where some phenomenon occurs, e.g. acoustic spectrum, visible spectrum.
power spectrum: the distribution as a function of frequency of the square of the amplitudes of the spectral components of a signal or noise. [2]
Note – The spectrum of an electromagnetic radiation, defined in chapter 845, can be considered as a power spectrum.
amplitude spectrum: the distribution as a function of frequency of the amplitude of the spectral components of a signal or noise, [3]
fgnievinski ( talk) 04:22, 12 December 2023 (UTC)phase spectrum: the distribution as a function of frequency of the initial phases of the spectral components of a signal or noise. [4]
Physics articles should focus on the physical phenomenon, not on the mathematics we use to describe it. The electromagnetic spectrum is not a function—that is a mathematical concept, not a physical one. It's not the domain either. I would rephrase what JBL wrote above this way: "The electromagnetic spectrum is the full range of electromagnetic radiation, from the lowest-frequency radio waves to the highest-frequency gamma rays." That gets us in the mindset of physics from the start and focuses on the topic itself, leaving the distraction of frequency vs wavelength vs photon energy for a subsequent sentence.-- Srleffler ( talk) 04:51, 12 December 2023 (UTC)
We should stick to the sources, especially secondary and tertiary sources, which give two clear meanings: EM spectral density and EM frequency domain.Except that they don't. The sources give one clear meaning for "electromagnetic spectrum" in its own right, and other clear meanings for other uses of the word "spectrum". XOR'easter ( talk) 15:44, 15 December 2023 (UTC)
Why didn't anyone notice the MIR and FIR values for Photon eV is reversed. Wrong numbers in the table. 65.36.54.181 ( talk) 13:01, 19 December 2023 (UTC)
I just stumbled upon the UV section: lots of "short wavelength" discussion. I encourage editors to avoid using "wavelength" in any sentence here about energy. Energy is proportional to frequency. Using the inversely proportional wavelength is unnecessarily confusing and physically not helpful. Johnjbarton ( talk) 21:30, 27 January 2024 (UTC)