Later, at page 105 (and figure 68) Feynman says that for class, the turn is 90 degrees, and not 180 as in Figure 41. What accounts for the difference ?
I don't understand, sorry. The path the light makes inside the glass (3-5-7) doesn't cancel out, because there are two shrinks by 0.2 caused by it (at points 4 and 6).
What does cancel out is that the path inside the glass on the way to A (3-5) sometimes cancels out the direct reflection off...
Hello,
This is my first post to physicsforums. I hope I've picked the right forum for this question, please correct me if not :blushing:
To answer my question you'll have to have the book "QED, the strange theory of light and matter" in front of your eyes.
I'm now reading Feynman's QED...