Intensity and the Double Slit Experiment.

In summary, the conversation discusses the derivation of a formula for the intensity of interfering waves and how the electric field components are combined from two different sources. The formula states that the intensity is proportional to the square of the combined value, but this seems to contradict the principle of energy conservation. However, it is later explained that in other areas, the waves are canceling out, resulting in the correct calculation of total energy. The concept of a "union" of fields is also discussed, with some confusion about its applicability in all situations.
  • #1
Sefrez
126
0
In viewing a derivation of the formula describing the intensity of the interfering waves, I noticed how the electric field components were combined - one from slit a, the other from slit b. The intensity is then proportional to the square of this value. But this would mean that two in phase waves of equal magnitude would result in 4 times the intensity of one alone. However, if you had two light sources of intensity I separate from one another and measured the energy per unit of time transferred to A area, shouldn't you only get twice the energy flow when then combining the two sources? Otherwise it seems energy is not conserved. In another way put: E^2 + E^2 ≠(E + E)^2 at which the first case in the derivation uses the latter.
 
Physics news on Phys.org
  • #2
You're overlooking that elsewhere the waves are canceling. When you calculate the total energy it comes out right.
 
  • #3
Yes, I believe I understand this. I guess what confuses me is the "union" of fields. It does't seem as if this thinking could be used under any situation. For example when all waves from two sources are in phase (not speaking as in a double split experiment.) Then all waves would be constructive.
 

1. What is the double slit experiment and why is it important in physics?

The double slit experiment is a fundamental experiment in quantum mechanics that demonstrates the wave-particle duality of light and matter. It involves shining a beam of particles or light through two parallel slits and observing the interference pattern that forms on the screen behind the slits. This experiment is important because it challenges our understanding of the behavior of particles and led to the development of new theories in physics.

2. How does the intensity of light or particles affect the double slit experiment?

The intensity of the light or particles used in the double slit experiment determines the brightness of the interference pattern on the screen. Higher intensity results in a brighter and more defined pattern, while lower intensity leads to a dimmer and less defined pattern. This is because the intensity of light or particles determines the number of photons or particles passing through the slits, which in turn affects the interference pattern.

3. Can the intensity of light or particles be changed during the double slit experiment?

Yes, the intensity of light or particles can be changed during the double slit experiment. This can be done by adjusting the source of light or particles, such as changing the power of the laser or the number of particles emitted. This will result in a change in the brightness and definition of the interference pattern on the screen.

4. How does the intensity of light or particles relate to the phenomenon of wave-particle duality?

The intensity of light or particles is closely related to the phenomenon of wave-particle duality. In the double slit experiment, light or particles behave like waves, creating an interference pattern on the screen. However, when observed at the slits, they behave like particles, passing through one of the slits and creating a single spot on the screen. This duality is further demonstrated by the fact that the intensity of light or particles affects the interference pattern, but not the behavior at the slits.

5. How is the intensity of light or particles measured in the double slit experiment?

The intensity of light or particles in the double slit experiment can be measured using a photodetector, which detects the number of photons or particles hitting it. This can be used to determine the intensity of the light or particles passing through the slits. Alternatively, the brightness of the interference pattern on the screen can also be used as an indication of the intensity of light or particles.

Similar threads

B Explanation for bright fringes in Single Slit Diffraction
    • Classical Physics
Replies
4
Views
327
B Young's Double slit experiment with different slit sizes
    • Classical Physics
Replies
20
Views
5K
I Young's double slit: why fringes gets dimmer and inconsistent?
    • Classical Physics
Replies
4
Views
2K
Intensity of central maximum when width of single slit is doubled
    • Introductory Physics Homework Help
Replies
13
Views
425
I Uncertainty in an experiment with an image viewed through a big slit
    • Classical Physics
Replies
3
Views
573
B Where Does Energy Go in Young's Double Slit Experiment?
    • Classical Physics
Replies
12
Views
2K
I "Wave-particle duality" and double-slit experiment
    • Quantum Physics
2
Replies
36
Views
1K
I Calculating Intensity in Single Slit Diffraction Experiments
    • Optics
Replies
17
Views
2K
I Double slit as a function of time
    • Quantum Physics
Replies
9
Views
776
I Can n-slit interference produce subwavelength stripes?
    • Optics
Replies
6
Views
797

Hot Threads

Recent Insights

Back
Top