Physics Help Forum interference and beat

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 Jan 25th 2015, 05:17 AM #1 Junior Member   Join Date: Jan 2015 Posts: 15 interference and beat For two waves, if it can be seen that after an interval of time no sound is heard, which option is liable for this incident? One option is interference of sound, and another is beat. I know that beat is one kind of interference. But sometimes I fail to make difference between them. If interference is liable for that incident, how will you explain the action of interference behind this? If I say that beat is not liable for this, what is the reason behind this?
Jan 25th 2015, 12:40 PM   #2

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 Originally Posted by Nousher For two waves, if it can be seen that after an interval of time no sound is heard, which option is liable for this incident?...
If the sound is not heard it would imply that you are at one of the points (nodes) of destructive interference. If the sound is not heard at any point then you are far from the source and cannot hear it because the intensity of the wave has been dissipated to the point where the sound simply is below hearing threshold. Beats have nothing to do with it.

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 Dec 21st 2015, 02:51 PM #3 Banned   Join Date: Dec 2015 Location: Tintagel,.Cornwall, UK Posts: 48 Sound and Beats. The beat is the result of two (or more) sounds mutually interferng. You get the some effect in radio-transmission except that then we call it "fading"". On squared paper plot two nearly-identical sine waves with a relevant difference in phase ... i.e. they start at different times. Now go up each vertical line of your graph, read off the instantan eous values of your two waveforms, add these together and plot the result as a third curve on the same squared grid. What do you get? A good use for your "Mathematical Tables". Ken Green
 Dec 22nd 2015, 03:29 PM #4 Senior Member     Join Date: Apr 2008 Location: Bedford, England Posts: 668 When I were a Lad... You are showing your age here Ken, no one uses graph paper these days... It all done via Excel (or similar computer package) now. I note, from your User Profile, that I am not that much younger than you, I can well remember how grateful I was to not to have to use graph paper any more. Youngsters nowadays don't realize how lucky they are... (Note tongue firmly in cheek) __________________ You have GOT to Laugh !
 Dec 23rd 2015, 01:22 PM #5 Banned   Join Date: Dec 2015 Location: Tintagel,.Cornwall, UK Posts: 48 Graph Paper Not sure whether or not to agree with you. Very convenient as you extract results to plot straight on to paper. Linear results on lin-lin paper ... straight line.. Log. result on log.-log. paper ... straight line ? Job not going according to plan? ... instant warning. I repeat: Computers.. Poof! Yong people these days have it MUCH too easy and live the lives of experts. Remember the undergraduate who caught me calibrating an aerial with thernocouple and Avometer - grade 1. He hammered the bench and stalked out shouting: "Isn't anything done in this place from first principles.". I rather enjoyed educating him !! Ken
 Dec 23rd 2015, 01:56 PM #6 Banned   Join Date: Dec 2015 Location: Tintagel,.Cornwall, UK Posts: 48 An indivisible particle. Oh, Topsquark, Here you hand me a tough one. There is little if any correlation between my work and standard acceepted Physics. I do not use any maths at all except in the standard exercise evaluating the properties of my proposed Atoms. But for my early grounding in Euclid I would have died an old and hopeful Man. (see for example "The Equilibrium Sphere" which explains/predicts superconductivity,) Yes I do believe, if any young brains could be brought to bear (with suitable computer skills, then it will likely be possible to forecast the physical attributes could you first describe the geometry of the Atomic/ molecular structure. Get rid of those test-tubes and bunsen burners !! At the behest of my Daughter (my Editor & DRIVER) I have tried to produce a simplified version. Never tackled anything so difficult and gave up at the last two fences - likely to explode. But, bless her, it resulted in advancing the work to where I now believe i can rid the world of that pesky GUT ! The Universe is fractal. If I can dig outt a working copy (it has seemingly destroyed this computer ) will PM a copy. Second volume even more raw at this moment. But please do go ahead and shoot to kill. Ken
 Dec 23rd 2015, 04:32 PM #7 Forum Admin     Join Date: Apr 2008 Location: On the dance floor, baby! Posts: 2,603 kengreen, I suspect that this is a reply to a post I made in another thread. Please stay on topic. -Dan __________________ Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup. See the forum rules here.
 Nov 16th 2016, 10:58 PM #8 Junior Member   Join Date: Sep 2016 Location: London Posts: 21 Interference and Beat Interference is a pattern that you see when you observe a superimposed wave. This means that they are the same, or nearly the same, frequency. Beats is a kind of interference that occurs when two waves at almost the same frequency alternately reinforce and cancel. For them to cancel perfectly, they also need to be of the same amplitude.

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