Quatum mechanics -- Interference?
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Since Einstein is rather inconveniently dead at the moment, I'll have to answer.  \n\n\nWhy we can't simply have a half a photon that goes undetected is a good question, from the information presented in that article, but a reason it can't work like that:\n\nThe energy of light is related to its wavelength, so if a photon split into two equal halves, then each would have twice the wavelength.  Of course, I'm kinda cheating here, since the relationship between energy and wavelength is one of the rules of photon quantization.  However, there's a very good theoretical reason for this: the ultraviolet catastophe.   See links below.\n\nThe "twin" in this case is really the same photon.  So, this is an example of superposition, which is similar to entanglement.  Entanglement is basically when a set of particles are put into superposition such that the outcome of a measurement on one depends on the measurement of the other.  In this case, the photon is simply in two possible paths through the beamsplitter until such time as it's measured.  Superposition is said to occur whenever a particle is put in a state such that it can have more than one observable outcome if measured.  Until such time that the photon hits one detector or another, it's both reflected off the mirror *and* passed through the mirror.  Yes, it seems like it really ougth to be one or another, doesn't it?  However, QM doesn't work that way.   \n\n\nIf there were three paths...  well, then there would be three paths.  It depends on what the detectors and other optical devices put in the path can do as far as how this would affect the whole behaviour of the system. \n\nThe example given there is the classic "interaction free measurement" trick, also sometimes called quantum interrogation.  It's an important function in ideas about quantum computing since it allows information about states to be retrieved without upsetting entangled states.\n\nIt's getting rather late in my current timezone, and I haven't had dinner yet.  I'll answer in more detail and answer your additional comments once I get some dinner in me.\n\nOK, a few additions...\n\nThe screen placed in either path breaks the single particle interference and gives rise to the possibility of detector B finding the photon, but it doesn't rule out the photon still ending up at detector A, and it also gives rise to the possibility that the photon gets absorbed by the screen.  However, the amazing thing is that if the photon does show up at detector B, then it will tell us that something is located in the optical path without ever having interacted with it.  Presto!  An interaction free measurement.  So, this both shows some interesting possibilities for quantum measurement tricks, which have implications for quantum computing, and shows one of the achilles' heels of the technique.  In this case we can do something which is impossible in a classical physics sense, but we also have three possible outcomes of the experiment, only one of which actually does anything interesting.  So, there are a lot of issues in the development of quantum computing that hinge on the ability to take advantage of these strange effects, but also give us good reliability of the answer.  Taking this trivial example, what we'd need is to develop a more complicated system in which the interaction free measurement effect occurs not 1/4 of the time (half the time the photon is absorbed, if not absorbed, half the time it ends up at A, which tells us nothing) but almost every time.  There are ways to do this, but it gets very complicated very quickly.  \n\nAs for how you get a single photon to work with in the first place...   We currently don't have the technology to simply conjure up a single photon reliably.  There are certainly hypothetical ways it can be done, but right now you just take a brief low intensity laser pulse, pass it through a filter that will
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http://www.dellamente.com/quicksand/doc/qsmyths.htm
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depends on the direction of the force
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i think the problem is when you try to apply general relativity - or gravity - to interaction betwen subatomic particles - especially when trying to understand how these forces worked during the first instant after the big bang. you wind up with nonsencial results - like zero equals one.
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Well, I think I found something; it says that the rule is part of the Newton-Cotes formulas (Isaac Newton and Roger Cotes).\n\nThis is the page where I found the info:\nhttp://www.absoluteastronomy.com/ref/trapezium_rule
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Yes, Richard Feynman suggested this way back when. \n\nThe original paper is available here: http://prola.aps.org/abstract/PR/v76/i6/p749_1\n\nWithout a subscription you'll only be able to read the abstract.
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Look\n\nhttp://www.quackwatch.org/01QuackeryRelatedTopics/DSH/msm.html
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This site has excellent applets on interference and diffraction.  Experiment with them to see how the wavelength and slit size affect the patterns, for example change the wavelength from blue to red light and see what happens.\nApplets here: http://electron9.phys.utk.edu/phys136d/modules/m9/diff.htm\nUse the links for Interference and Double Slit Interference, or Single Slit Diffraction.
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Cirric is always right.  Thought he was a robot did you?\n   On this site put sonic wave included in your question.\n  Or put the equivalence should equal gravity interactive with\n   magnesiums.
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1)  I'm not entirely sure.  It may just be the preference of that publisher, or just that the quantities being compared were not measured more accurately than to two places.\n\n2)  The coeffecient of friction is basically a measure of how well two surfaces slide against one another.  Pressing down simply increases the force, it does not necessarily change the structure of the surfaces in contact.\n\n3)  The coefficient of friction has no units because it is a ratio.  If you were to write out the units being compared in a fraction, say 2 Newtons / 4 Newtons, the units would cancel out when divided.
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Its' probably a rounding error. It would depend on which masses for the elements you use, how precise you want to be.
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I believe you will find the solution to your problem here:\n\nhttp://www.engineeringtoolbox.com/bernouilli-equation-d_183.html
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Quantum mechanics is fascinating, as Einstein's famous quote that "God does not play dice with the universe" is turned on its head.  The random nature associated with the inner workings of atoms and quarks is astonishing when one considers that despite all of the unpredictability of subatomic activity, things in the macroscopic world follow predictable patterns that seem to defy common sense.
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I am terribly afraid of the equilibrium problem.. the first one on the free response!!! well, good luck!
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Well that book must have a misprint or something because q=CV is not accurate. Actually if the potential of a outside conductor depends on the size, then this is a variable dependent, (and therefore mutable) in structure, shape, and amount of conduction based on the charge of q. For if C=q/v, then the isolated conductor's potential to change will be hinder and therefore not fully capable of allowing a full transformation for V due to the charge (power) of q.
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I am sorry I can not provide you with an answer to your question. However it might help you get more answers if you put this question in again but put it in the Science and Mathmatics section. Under Physics. I think there are more people willing to help you out there!
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One end of the galvanometer is connected between P and Q; the other end between R and S.\n\nYou have one sided deflection even after checking for any wrong connections.\n\nIt means proper ratio of resistances is not chosen.\n\nThe resistances cannot be taken at random.  P/ Q must be nearly equal to R/S.\n\nAdjust the resistances so that P/ Q must be nearly equal to R/S.\n\nWhen these ratios differ much you will get one sided deflection.