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forsure (for sure) 于 (Sat Jun 17 00:05:13 2006) 提到:
A straight pipe with the opening cross section S is filled with
dust. The number of dust particles is N>>1, cross section of
each particle is s, and the total cross-section Ns=S. The
particles are blocking light coming through the pipe, but not
completely, because their shadows overlap due to random positions.
What is the pipe's light transmission coefficient?
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