Talk:Inverse-square law

message: The first diagram I ever saw of the inverse square law was better, in my opinion.  It showed ...
Nevermind, I found some similar ones:   — Omegatron 18:16, 19 February 2006 (UTC)
thread_title:  Diagram 

message: It would be appropriate to add the word "Interestingly" to the start of this section, I am perplexed attempting to explain connection Omeganumber (talk) 02:26, 1 March 2008 (UTC)
thread_title:  Light and other electromagnetic radiation 

message: how do you cite it?  —Preceding unsigned comment added by 24.236.97.242 (talk) 18:34, 7 March 2008 (UTC)
thread_title:  citation 

message: Well I finally got around to drawing a new diagram of the inverse square law. Comments/Suggestions etc? It's not the easiest law to illustrate... -- Borb (talk) 14:05, 2 April 2008 (UTC)
thread_title:  New Diagram! 

message: This is intended as constructive criticism regarding the "acoustics" entries on the inverse square law page. I don't like to see popular misconceptions perpetuated. I guess if I knew how to present what I feel is the correct information on the page I would have edited it rather than posing a comment here, but I am an absolute novice when it comes to Wikipedia editing. But to get to the point…
The propagation of sound *does* obey the inverse square law in exactly the same way as electromagnetic radiation does. Sound *pressure* is not a valid equivalent to electromagnetic radiated power as a source – you are not comparing like with like. As the distance from the source increases, the acoustic *power* fall as the inverse square of the distance – double the distance means a quarter of the power, or 6·02dB; this equates to (and is the cause of) a halving of sound *pressure*, since pressure is proportional to the square root of power times radiation resistance, the latter being constant.
If my knowledge of acoustics is faulty, then please disregard the foregoing comments, if not, then maybe you might consider editing the relevant sections of the page accordingly.
S Sycamore (talk) 19:16, 8 August 2008 (UTC)
replies: text: If anything, the section as written is confusing to the layperson, both physically and mathematically.  The section reads "In acoustics one usually measures the sound pressure at a given distance r from the source using the 1/r law. Since intensity is proportional to the square of pressure amplitude, this is just a variation on the inverse-square law." On its face, this seems to suggest that this whole section does not belong on this page at all, as it is inversely proportional and not inverse-square. Could someone clarify (for the layman) the difference between "pressure" and "intensity," as that seems to be the sticking point?  NewkirkPlaza (talk) 19:19, 22 October 2014 (UTC)
replies: text:  I removed acoustics section - it may be correct, but not explained to a depth that makes it fit (understandable) into the article. I think it would be hard or impossible to fix that, because much depends on the use of dB in that section, which makes the numbers hard to understand. Also, the reader would need to understand the relation of sound power, amplitude, pressure and loudness (or most of it) to make sense of the calculations in terms of perceived sound intensity. (Oh, and the dB is usually referring to a standardized psychoacoustic weighting of frequencies, which complicates it some more.)  — Preceding unsigned comment added by Volker Siegel (talk • contribs) 14:10, 29 July 2016 (UTC)
thread_title:  Acoustics section 

message: Is it possible that the LED device .. designed to remove infrared radiation (IR) from the white light spectrum does not follow the Inverse-square law as is? Sorta meaning IR helps carry light through distance?Greg0658 (talk) 16:42, 9 February 2009 (UTC)
replies: text: No the inverse square law is a spreading function and is independent of the spectrum of radiation. The typical LED has a built in reflector and lenses that direct the light in one direction. Inverse square still applies but it's as if the point source was originated somewhere far to the rear of the actual LED so the fall of is less per unit distance after the LED surface. 12.106.237.2 (talk) 17:15, 15 April 2010 (UTC)
thread_title:  Light Emitting Diodes (LEDs) 

message: From  Ryer, A, "The Light Measurement Handbook", 1997 : p.26. (The chapter is also available online here)
Under the heading "Point Source Approximation" Ryer describes 1) some practical limitations of the inverse square rule, 2) a more accurate and encompassing alternative formula which includes non-point sources. 
If I have interpreted correctly: for illuminance from a non-point-source - ie where the diameter of the light source is more than 1/5th of the distance - the following formula may be more useful: E = Lr2/(r2 + d2); where r= source radius and d= distance.
This would certainly seem like a valid addition to the Inverse-square_law#Light_and_other_electromagnetic_radiation section. Perhaps it would also be applicable in other contexts ? --Redbobblehat (talk) 14:07, 10 February 2009 (UTC)
thread_title:  accuracy - Point Source Approximation 

message: :I was trying to look up a solution to a problem I had run into regarding Inverse Square law calculations given a distance variable of 0 (which would involve division by 0, which is unallowed), although I see someone has made a comment referring to limitations of inverse square law, and that may be one of them. 
:However, much of the work I am doing involves simulated sunlight, and I noticed the potentially useful mention of the relative illumination of the sun at the surfaces of Mercury and the Earth; but I was a bit puzzled as to why this is presented in watts? Watts are a measurement of energy consumption, not illumination: for that reason, it's impossible to convert between watts and candles since energy consumption given an illuminative power is variable: in other words, different lights produce varying amounts of illumination given the same energy consumption. So I can't convert the value to a useful illuminative power. Perhaps this should be given in candles instead? LSmok3 Talk 12:10, 7 December 2009 (UTC)
thread_title:  Watts Versus Candles 

message: This article could greatly benefit by the addition of a clear summary for the layman appended near the beginning. I came away with not much greater an understanding of the concept of the inverse-square law than I had before I read this. Not enough, I had to go to several other web sources to acquire a basic understanding. I am a well-educated person without much mathematics (which is a large demographic). Someone with a thorough grasp of the term and its applications, as well as related concepts, should write a brief non-technical, non-specialist definition and place it near the beginning of the article. The depth and breadth of Wikipedia articles is commendable and very useful, but just as often readers seek to gain a basic grasp of a thoroughly unfamiliar subject. We can do both here, it just needs 50-100 words of cogent definition added.Googlyelmo (talk) 19:06, 22 October 2010 (UTC)
thread_title:  A clearer summary definition for the layman is needed 

message: Hi there Wikipedians- I removed the part of the sentence under 'gravitation' which read " instead of the guess of Johannes Kepler at inverse distance dependence"
I'm researching pre-Newtonian gravitation and can't find any other mention that Kepler accepted a 1/d law for gravity. He certianly used a 1/d relation for orbital velocity- but that's not the same thing at all as gravitational attraction. If someone finds a reference then I think it could be reintroduced. In the meantime it shouldn't be there as it's unsubstantiated. 188.220.171.33 (talk) 17:33, 26 November 2010 (UTC)
thread_title:  Kepler's beliefs 

message: I just noticed an error in the introductional picture about the flux behaviour. The intersection points of the three central rays with the third distance sphere are obviously wrong (compared to the first two spheres). If you klick on the image it is presented correctly, so it should be an easy matter to change this. Anyways, i have no idea how to do that. Greetings to all fans of the inverse square law.  — Preceding unsigned comment added by 92.224.175.6 (talk) 11:37, 10 September 2011 (UTC)
thread_title:  The Flux Visualisation 

message: The article should present a mathematical discussion of the force field of four special cases.
# The outside of a spherical charge distribution (equal to a point charge)
# The inside of a spherical charge distribution (zero)
# Infinitely long linear charge. (inverse to distance)
# Infinitely large planar charge. (constant at all distances from plane.)
The force should be derived – not only from the flux, but also by integrating over an even distribution of charges. -- Petri Krohn (talk) 22:52, 17 January 2012 (UTC)
thread_title:  To do: some mathematics 

message: What is the relation of the ISL to space-time? --TheLastWordSword (talk) 17:37, 3 August 2015 (UTC)
thread_title:  Entropy and energy density 

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thread_title:  External links modified 

message: The reference to Barrow's 2020 is not an original reference, and there are mathematical problems which would confuse a reader grasping for an understanding, or even a professional for that matter. Hyperbolic geometry in relation to general relativity has been dealt with extensively in the literature i.e. in monograph form. See, for examples, the Wikipedia references.
Citing lecture notes (by Guth), which contain no references hardly does the subject of the applications of nun euclidean geometries justice. Why should lecture notes replace a vast literature on the subject? Bernhlav (talk) 15:39, 19 March 2024 (UTC)
thread_title:  Non euclidean geometries