This is the first episode about coherence and how this wave phenomenon can cause waves to behave like localized entities.
Unfortunately the quantum (or corpuscular) description of light leads to a lot of confusion. The goal of this video is to describe "quantized" behavior of light purely from wave principles.
Contents:
0:00 Intro
1:04 Historical perspective
2:58 Quantization and the photoelectric effect
6:42 Light is just waves
7:24 Coherence explained
12:54 Temporal coherence as a sum of EM-fields
16:47 Coherence length vs. spectral band width
20:25 experiments on the coherence length of light
Link to the referenced Physics Explained video:
• What is the Heisenberg...
A sharp viewer noted that there is an error in the formula on the sheet at 27:25 : The product of delta time and delta energy in the Heisenberg uncertainty principle is not equal to (h*4*pi) but h/(4*pi), so a much smaller value. This also makes the value of delta frequency times delta time 1/(4*pi) not 4*pi Unfortunately I did not double check the values. Thanks for pointing this out Steve.
In this video short clips of other RU-vid channels were used for illustration. Because of their short length and purpose, they are to be considered to be "fair use".
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Did I forget anyone? Please let me know and I'll set things straight.
End music: Floating; The Early Birds. © JJM Vleggaar, 1999
7 июн 2024