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location Beijing, China
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visits member for 3 years, 11 months
seen Oct 11 at 17:14

Beauty is simple


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Jun
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answered Radiative transfer equation solution
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Aug
6
revised How can a laser pointer have range of several kilometers in atmosphere?
typeos
Aug
6
comment How can a laser pointer have range of several kilometers in atmosphere?
Those laser pointers (there are 5 actually) are used to play as artificial stars. They are more powerful (5W each) than handheld device, but ARE still pointers and have a range of several kilometers. Why do you think they are different ?
Aug
6
revised How can a laser pointer have range of several kilometers in atmosphere?
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revised How can a laser pointer have range of several kilometers in atmosphere?
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6
awarded  Critic
Aug
6
comment How can a laser pointer have range of several kilometers in atmosphere?
Yep, I made a mistake here. The labled power on laser pointers is output power. The deviation between input power and output value is conversion efficiency. The typical input power of a 50mW pointer is about 0.5 W. But This is not the point.
Aug
6
revised How can a laser pointer have range of several kilometers in atmosphere?
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Aug
6
answered How can a laser pointer have range of several kilometers in atmosphere?
Jun
2
answered Does Earth have a code name?