Question about a double-slit experiment

In summary, the problem involves a sheet of plastic with an index of refraction of 1.6 covering one slit of a double-slit. When illuminated with monochromatic light of wavelength 586 nm, the center of the screen on the other side appears dark. To achieve destructive interference, the light must have a phase difference of 180 degrees. The thickness of the plastic affects the wavelength of light in the material and the phase change in passing through it, ultimately determining the minimum thickness needed for the light to have the necessary phase difference.
  • #1
Nivlac2425
54
0

Homework Statement



A sheet of plastic, n=1.6, covers the entrance of one slit of a double-slit. When the double-slit is illuminated by monochromatic light with wavelength = 586 nm, the center of the screen on the other side of the double-slit appears dark rather than light. What is the minimum thickness of this sheet of plastic?


Homework Equations





The Attempt at a Solution



I know that in order for the bright area on the screen to be dark instead of light, destructive interference must be occurring.
I can also find the velocity, v, of the light in the plastic with the equation n=c/v
 
Physics news on Phys.org
  • #2
You can also find the phase difference in the light between the two slits. You need equations. Maybe read the section in your book about the "Double Slit Experiment".
 
  • #3
To have destructive interference, the light would have to have a 180degree phase difference right? But how does the thickness of the plastic affect the phase difference of the light in respect to the unaffected light?

Thanks
 
  • #4
Nivlac2425 said:
But how does the thickness of the plastic affect the phase difference of the light in respect to the unaffected light?
Compare the phase shift of light going through a thickness of plastic versus light going through the same thickness of air (or vacuum). Hint: Consider how the wavelength changes in the plastic.
 
  • #5
The wavelength is decreased in the plastic, but by how much? Thickness probably affects that, but what else, the index of refraction? It would need a net phase change of 180 degrees to cause destructive interference.

Thanks
 
  • #6
The wavelength of light in a material depends on the material's index of refraction. The phase change in passing through the material depends on the material's thickness and the wavelength of light in the material.
 

1. What is a double-slit experiment?

A double-slit experiment is a classic physics experiment that demonstrates the wave-particle duality of light. It involves shining a beam of light through two narrow slits and observing the resulting interference pattern on a screen behind the slits.

2. What does the double-slit experiment tell us about the nature of light?

The double-slit experiment shows that light behaves both as a wave and as a particle. When light passes through the slits, it creates an interference pattern, suggesting that it behaves as a wave. However, when individual particles of light (photons) are observed, they act like discrete particles, suggesting that light also behaves as a particle.

3. How does the double-slit experiment relate to quantum mechanics?

The double-slit experiment is one of the key experiments that led to the development of quantum mechanics. The results of the experiment challenged traditional ideas about the nature of light and matter, and ultimately contributed to the development of the quantum theory of matter and energy.

4. Can the double-slit experiment be performed with other particles besides light?

Yes, the double-slit experiment has been performed with various particles, including electrons, neutrons, and even large molecules. The results have been consistent with those of the original experiment with light, further supporting the idea that all particles exhibit wave-like behavior.

5. What practical applications does the double-slit experiment have?

The double-slit experiment has numerous practical applications, including in the fields of optics, quantum computing, and quantum cryptography. It also helps us to better understand the behavior of particles and the fundamental laws of physics.

Similar threads

  • Introductory Physics Homework Help
Replies
8
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
516
  • Introductory Physics Homework Help
Replies
6
Views
3K
  • Introductory Physics Homework Help
Replies
3
Views
5K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
6K
Replies
3
Views
750
  • Introductory Physics Homework Help
Replies
3
Views
2K
Replies
32
Views
2K
  • Introductory Physics Homework Help
Replies
14
Views
4K
Back
Top