Opaque-wall-with-hole argument from Feynman lectures

In summary, the conversation discusses an argument from chapter 31 of Feynman lectures vol I about the electric field on the other side of an opaque wall with holes. The argument claims that the fields arriving at the wall, not being changed by the plugs, can be used to support the equation Ewall=E'wall, which represents the fields generated by the wall charges at point P. This approximation works well with larger holes and was also used in a previous chapter where the hole was half the size of an infinite plane. However, it is unclear when this approximation can still hold for larger holes. The conversation also includes a link to a paper discussing Babinet's Principle.
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euphoricrhino
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In Feynman lectures vol I, last part of chapter 31, there was this argument about electric field on the other side of the opaque wall with holes.
The argument is attached below. I'm having a hard time understanding the claim in the red box. In particular, I failed to see how "fields arrive at the wall" not being changed by the plugs can be an argument for Ewall=E'wall, which are the fields generated by the wall charges at point P.
This argument seems to say that the approximation in the claim works well with "big" holes (not holes with size comparable to the wavelength). And the result was also used in the previous chapter, where the hole is pretty much half of the infinite plane. I'm failing to see when the hole is this big, Ewall=E'wall can still hold.

Did I miss something obvious? Can someone please enlighten me?
Thanks!
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1. What is the "Opaque-wall-with-hole argument" from Feynman lectures?

The "Opaque-wall-with-hole argument" is a thought experiment proposed by physicist Richard Feynman to explain the concept of quantum mechanics. It involves a wall with a small hole in it, and a light source on one side of the wall. According to classical physics, the light would simply pass through the hole and create a bright spot on the other side. However, in quantum mechanics, the light would also create a diffraction pattern, demonstrating the wave-like nature of light.

2. How does the "Opaque-wall-with-hole argument" support the concept of quantum mechanics?

The "Opaque-wall-with-hole argument" demonstrates the wave-particle duality of light, which is a fundamental principle of quantum mechanics. It shows that light can behave as both a wave and a particle, depending on the experimental setup. This supports the idea that particles at the quantum level do not have a definite position or trajectory, and can exist in multiple states simultaneously.

3. Can the "Opaque-wall-with-hole argument" be applied to other particles besides light?

Yes, the "Opaque-wall-with-hole argument" can be applied to other particles, such as electrons. In fact, this thought experiment has been used to demonstrate the wave-like behavior of electrons and other subatomic particles. It has also been extended to explain other phenomena, such as the double-slit experiment, which further supports the principles of quantum mechanics.

4. What are the implications of the "Opaque-wall-with-hole argument" on our understanding of the physical world?

The "Opaque-wall-with-hole argument" challenges our traditional understanding of the physical world and forces us to rethink the nature of reality. It suggests that at the quantum level, the behavior of particles is unpredictable and can only be described probabilistically. This has significant implications for our understanding of causality, determinism, and the fundamental laws of physics.

5. How does the "Opaque-wall-with-hole argument" relate to the uncertainty principle?

The "Opaque-wall-with-hole argument" is closely related to the uncertainty principle, which states that it is impossible to know both the exact position and momentum of a particle at the same time. The thought experiment demonstrates this principle by showing that the more accurately we measure the position of a particle, the less we know about its momentum, and vice versa. This highlights the inherent uncertainty and unpredictability of the quantum world.

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