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Saibottomus
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Hello PF! I've got a strange question for you physics boffins; assuming for a moment that lasers obeyed the inverse square law, what range would a typical 1mW red laser have in the atmosphere?
cepheid said:Welcome to PF,
Only things that emit isotropically (i.e. the same in all directions) obey the inverse square law. Also, it's unclear what you mean by "what range" would the laser have? Do you mean how far away could you be from the source of the laser and still detect emission from it? You'd have to specify what the sensitivity limit of your detector was, and it would also depend on what the background noise level was.
Depends on the laser design and the eye.Saibottomus said:At approximately what distance would the laser not be detectable if shone directly into the observer's eye.
Thanks for your reply mfb. So if (hypothetically) the "brightness" (somehow) fell off with the square of the distance of the observer from the source, what would that reduce the range to?mfb said:~1000 photons/s seems realistic
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1mW of ~700nm corresponds to ~4*10^15 photons/s.
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>500km.
It does so for large distances, and I already took this into account with the assumption that the spread is ~1cm over 10m distance.So if (hypothetically) the "brightness" (somehow) fell off with the square of the distance of the observer from the source
The Inverse Square Law states that the intensity of a source of radiation, such as a laser, is inversely proportional to the square of the distance from the source. This means that as the distance from the source increases, the intensity of the radiation decreases.
The Inverse Square Law applies to a 1mW laser range in the sense that the intensity of the laser decreases as the distance from the source increases. For example, at a distance of 1 meter from the laser, the intensity would be 1mW, but at a distance of 2 meters, the intensity would be 0.25mW.
The Inverse Square Law is important in laser safety because it helps determine the safe distance for individuals to be from a laser source. As the distance from the laser increases, the intensity decreases, making it safer for individuals to be exposed to the radiation.
The Inverse Square Law affects the range of a 1mW laser by limiting how far the laser can travel before the intensity becomes too low to be detected. As the distance from the laser increases, the intensity decreases, making it difficult to detect the laser beam beyond a certain distance.
Yes, the Inverse Square Law can be applied to other sources of radiation, such as light bulbs or radio waves. It is a fundamental principle of physics that applies to any type of radiation that spreads out in all directions from a source.