Question about double-slit experiment

  • #1
Jason Ko
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Will the fringes be brighter if I use a raser with higher intensity? And can I improve the experiment by using higher wavelength incident rays so as to observe more bright fringes?
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  • #2
If you use a laser of higher intensity the locations where bright fringes appear will receive more photons per second so they will be brighter.

Why do you think that increasing the wavelength will increase he number of bright fringes? What equation do you have in mind? Also, in what way do you think the experiment will be improved if you increase the number of bright fringes?
 
  • #3
kuruman said:
If you use a laser of higher intensity the locations where bright fringes appear will receive more photons per second so they will be brighter.

Why do you think that increasing the wavelength will increase he number of bright fringes? What equation do you have in mind? Also, in what way do you think the experiment will be improved if you increase the number of bright fringes?
The diffraction effect will enhance as the wavelength has increased, so the bright fringes will span wider. If the number of bright fringes has increased, the measurement will be more accurate.
 
  • #4
Jason Ko said:
The diffraction effect will enhance as the wavelength has increased, so the bright fringes will span wider. If the number of bright fringes has increased, the measurement will be more accurate.
I repeat, what mathematical equation says that the number of fringes increases as the wavelength increases? You need to understand this point before you start thinking about increasing the accuracy of the experiment.

Also, you did not explain why more fringes means more accurate measurement. What exactly will you be measuring that will have its accuracy increased when you have more bright fringes?
 
  • #5
As I'll measure the distance spanned by several bright fringes and then determine the fringe separation. I think more fringes will lead to a better evaluation of fringe separation.
 
  • #6
kuruman said:
I repeat, what mathematical equation says that the number of fringes increases as the wavelength increases? You need to understand this point before you start thinking about increasing the accuracy of the experiment.

Also, you did not explain why more fringes means more accurate measurement. What exactly will you be measuring that will have its accuracy increased when you have more bright fringes?
I think I've made thing wrong. mλ=asinθ, larger wavelength means larger θ, so fewer fringes will be formed.
 
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  • #7
Jason Ko said:
I think I've made thing wrong. mλ=asinθ, larger wavelength means larger θ, so fewer fringes will be formed.
Now you got the idea. So if you want to have more fringes, you have to decrease the wavelength.
 
  • #8
kuruman said:
Now you got the idea. So if you want to have more fringes, you have to decrease the wavelength.
Thks a lot!
 
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Related to Question about double-slit experiment

What is the double-slit experiment?

The double-slit experiment is a fundamental demonstration in quantum mechanics where particles such as electrons or photons are passed through two closely spaced slits. The resulting pattern on a detection screen shows interference fringes, suggesting wave-like behavior, even when particles are sent one at a time. This experiment highlights the wave-particle duality of quantum objects.

Why is the double-slit experiment important?

The double-slit experiment is important because it challenges classical intuitions about particles and waves. It provides direct evidence of the wave-particle duality, a cornerstone of quantum mechanics, and raises profound questions about the nature of reality, observation, and measurement in the quantum realm.

What happens when you observe which slit the particle goes through?

When an observation is made to determine which slit the particle goes through, the interference pattern typically observed disappears, and the particles behave more like classical particles, producing two distinct clusters on the detection screen. This phenomenon illustrates the principle that measurement affects the system being observed.

Can the double-slit experiment be performed with larger objects?

Yes, the double-slit experiment can, in principle, be performed with larger objects. Experiments have been conducted with molecules and even small clusters of atoms, and they still show interference patterns, indicating wave-like behavior. However, as the size of the objects increases, maintaining coherence and preventing decoherence becomes significantly more challenging.

What does the double-slit experiment tell us about the nature of reality?

The double-slit experiment suggests that particles do not have definite positions or paths until they are observed. It implies that reality at the quantum level is fundamentally probabilistic and that particles can exist in a superposition of states. This challenges classical notions of determinism and locality, leading to various interpretations of quantum mechanics, such as the Copenhagen interpretation, many-worlds interpretation, and others.

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