**Ask a monkey a physics question thread**

[Renton]

who needs ascii when I know how to use autocad?






The green object is a cross section of a tube of inside diameter 1 unit and length 5 units. The cyan arcs represent the propagating EM wave, the dashed grey arcs represent the part of that wave that has been blocked by the tube, and the red radials show the density of the probability. Unless I'm doing it wrong, it appears that the photon only has about a 4% chance of escaping the tube.

[MadMojoMonkey]

who needs ascii when I know how to use autocad?






The green object is a cross section of a tube of inside diameter 1 unit and length 5 units. The cyan arcs represent the propagating EM wave, the dashed grey arcs represent the part of that wave that has been blocked by the tube, and the red radials show the density of the probability. Unless I'm doing it wrong, it appears that the photon only has about a 4% chance of escaping the tube.

Just to be clear to anyone following the thread: This question was erroneously posted to the Randomness thread - which is appropriate from time to time, I think - and I answered the questions there.

Short answer is that this is exactly the kind of picture I was visualizing and it sums up the classical situation perfectly well.

It falls short for the Quantum Mechanical effects. The photons which pass "near" the edge of the tube will be diffracted and will experience constructive and destructive interference. This will make a "rippled" boundary to the spot this device would project on a wall.

Also, it misses the fact that the tube absorbing the photons is absorbing their energy. This will cause the tube to heat until it's glowing and radiating an equal amount to it's intake.