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60 votes
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Double slit experiment at home failed

In order to see the interference fringes, four conditions must be fulfilled: Your light source either has to be point-like or very far away from the slits, Your light source must be monochromatic* (i....
probably_someone's user avatar
39 votes

Why is the shape of the fringes in Young's double slit experiment hyperbolic?

I will give you the mathematical details at the last, first just visualize what is going on. I am assuming that slits are like pinholes because if you took into account that they are thin rectangles ...
Yaman Sanghavi's user avatar
30 votes
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If a thousand people whisper inaudibly, will the resulting sound be audible?

Yes, always. I would like to disagree with stafusa's answer here, expanding on Rod's comment. Interference will not occur, since for whispering the sources of sound will be statistically independent. ...
Wolpertinger's user avatar
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30 votes
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A light problem: What happens when light completely destructively interferes?

The energy went back into your spherical source. For the first pulse the source had to provide energy. For the second pulse the source had to absorb energy. The mistake is simply assuming that the ...
Dale's user avatar
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25 votes
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Why is it difficult for water waves to cancel each other?

Interference requires exactly same frequency in both the sources and also needs them to be coherent i.e. their phase relation must remain same throughout. It's very hard to create such things for ...
Ari's user avatar
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23 votes

Is interference of light a quantum phenomenon?

What are these? Can a complex electric field be measured with any instrument? I guess, it cannot. Then, I would say, it cannot be classical, since classical quantities should be physical, in a sense ...
Dale's user avatar
  • 102k
22 votes

Question on wave interference?

Actually, you're completely right. Most treatments of the double slit involve some kind of simplification. The usual idea is that we approximate each slit in the double slit to be a point source, so ...
Maximal Ideal's user avatar
21 votes

If a thousand people whisper inaudibly, will the resulting sound be audible?

The amplitude of the sum of $1000$ equally loud uncorrelated noises will be about $\surd1000$, or approximately $32$, times the amplitude of a single noise. That might be enough to make an inaudible ...
John Bentin's user avatar
18 votes
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Why does a green stoplight interfere with FM radio reception (more than yellow)?

At those intersections there are sensors buried in the asphalt which detect the presence of cars waiting for the light to change. The sensor is a large circular coil of wire which is fed a high-...
niels nielsen's user avatar
17 votes

Is my understanding of the delayed choice quantum eraser correct?

This is going to be a long answer because there is a lot to unpack here. I'm going to briefly go over your questions about your understanding, then analyze the experiment from the video in detail, ...
benrg's user avatar
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17 votes

What happens when the amplitudes of interfering waves is different in the phenomenon of beats?

As an illustration to the other answers, here are two waves that we'll later superimpose (their frequencies ratio $\nu_1/\nu_2=15/16$): Their superposition with identical amplitudes of 1 will look ...
Ruslan's user avatar
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17 votes

Does the particle interfere with itself, or the observer?

The term 'observe' does not mean watching the experiments from a camouflaged hideout so that no one notices you are there. 'Observe' here means 'making a measurement' and hence interacting with the ...
SuperCiocia's user avatar
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16 votes

Confused by interference patterns created by a tuning fork

Tuning forks are more complicated than the simple picture you posted. Because there are two tines, they will emit sound more like quadrapoles (i.e, with a kind of clover-leaf loudness pattern) than ...
Jonathan Stott's user avatar
16 votes

Avoiding radar detection using active noise control instead of a stealth fuselage

To get an idea of the difficulties, we will consider a similar problem with sound. There are places with names like "Echo canyon". If you shout, the sound reflects of a nearby canyon wall ...
mmesser314's user avatar
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14 votes

If a thousand people whisper inaudibly, will the resulting sound be audible?

The answer is "maybe". 1000 inaudible whispers may still be inaudible; the question you probably meant to ask is "would the sound of 1000 people whispering at the same time be louder than the sound of ...
Floris's user avatar
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14 votes

If two sound waves that are different frequencies create beats that occur several hundred times per second, can you hear this effect as its own tone?

Yes - American Technology Corporation, Woody Norris invented a phased array consisting of ultrasonic transducers; pairs that transmit two ultrasonic frequencies that are slightly different by a ...
docscience's user avatar
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14 votes
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Why does fringe width in double slit experiment remain constant if slits get narrower?

If I'm misunderstanding anything about your question, feel free to tell me. As I derived in this post, the (one-dimensional) formula for the double-slit intensity (in the Fraunhofer regime) is $$ I(\...
Maximal Ideal's user avatar
14 votes

Sound waves adding up

Since the phases are random, the waves do not add coherently... but neither do they cancel coherently. Furthermore, loudness is really a measure of the intensity of the sound. Thus, if we consider a ...
Roger V.'s user avatar
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14 votes

Is interference of light a quantum phenomenon?

Interference is a wave phenomenon. E.g., sound waves interfere, waves on water surface interfere. Interference is quantum to the extent that quantum objects exhibit both wave an particle properties. ...
Roger V.'s user avatar
  • 59.3k
14 votes

Avoiding radar detection using active noise control instead of a stealth fuselage

The essential problem with that is that transmitting emits energy. You can cancel out the reflection in a particular direction this way, but in other directions it won't cancel. In effect, you're ...
John Doty's user avatar
  • 21.2k
13 votes

Why don't the colors in an oil slick change as I walk past?

I did a little simulation using this software I wrote. The first box is air-oil-water at normal incidence, the second is looking at 45 degrees: (Your youtube video is not truly air/oil/water, but ...
Steve Byrnes's user avatar
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13 votes
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Michelson interferometer circular fringes

Here is a schematic diagram to show how the circular fringes are formed using the Michelson interferometer. These fringes are sometimes called fringes of equal inclination or Haidinger fringes. The ...
Farcher's user avatar
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13 votes

Can two waves interfere head on?

Can two waves (like sound or electromagnetic waves) interfere head-on? Yes. When waves add in a superposition it is called interference. Two waves heading towards each other with have interference. ...
BioPhysicist's user avatar
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13 votes

Why is intensity additive?

In a similar question, the good answer https://physics.stackexchange.com/a/714653/219989 shows a calculation of how when you have N sound waves with identical frequency - but uniformly distributed ...
Nadav Har'El's user avatar
  • 2,832
12 votes

Fringe width and spacing and number of slits in diffraction experiments

The first thing to note is that each of the slits produces a diffraction pattern the width of which is controlled by the width of the slit and the wavelength of the light. The amount of light ...
Farcher's user avatar
  • 96.9k
12 votes

What is the explanation for the interference patterns in MWI?

There doesn't exist any "totally well-defined" realization of MWI but its champions want to agree with the basic experimental facts so they would almost certainly say that there is no splitting of the ...
LuboŇ° Motl's user avatar
12 votes

If a thousand people whisper inaudibly, will the resulting sound be audible?

Yes, and if done carefully, not only audible, but also understandable. [Update: indeed, see the answer from Floris - include audio files to prove it!] For example, they should whisper exactly ...
stafusa's user avatar
  • 12.4k
12 votes

If a thousand people whisper inaudibly, will the resulting sound be audible?

I think it depends on what you mean by "whispering inaudibly." There are stage whispers, which are actually meant to be heard from far off, and real whispers, meant to be heard by the person next to ...
rob's user avatar
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