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Author Topic: Do photons cancel each other out?  (Read 1337 times)

Offline acecharly

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Do photons cancel each other out?
« on: 29/03/2014 14:36:57 »
If 4 people stand with there backs against the walls in a room how can i see the person on the opposite side of the room when the people to my left and right can also see each other? Why doesnt there image block mine and ours block theirs?



 

Offline RD

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Re: Do photons cancel each other out?
« Reply #1 on: 29/03/2014 15:35:20 »
Light can cancel out via destructive-interference:
The apparent black-hole in this soap-film isn't really a hole but an area where there is almost-total destructive-interference ...


http://en.wikipedia.org/wiki/Interference_%28wave_propagation%29

For this total destructive interference to happen, the interfering light waves must match exactly :
 same frequency, and exactly antiphase.

NB: the photons interfere with, but don't annihilate, each another.
http://en.wikipedia.org/wiki/Superposition_principle#Application_to_waves
« Last Edit: 29/03/2014 15:46:10 by RD »
 

Offline syhprum

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Re: Do photons cancel each other out?
« Reply #2 on: 29/03/2014 17:01:45 »
if you drive around listening to MW broadcasts you will find spots where the synchronised transmitters interfere and block each other out, this was the basis for a war time aircraft navigation system.
When photons are considered as waves this is easy to visualise but when they are considered as particles the matter becomes much more complex and QM must be invoked.
 

Offline Pmb

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Re: Do photons cancel each other out?
« Reply #3 on: 30/03/2014 05:35:50 »
If 4 people stand with there backs against the walls in a room how can i see the person on the opposite side of the room when the people to my left and right can also see each other? Why doesnt there image block mine and ours block theirs?
The light rays that are emitted from across the room are not interfering with any other beams of light by the time it reaches your eyes. Light is only distorted when it's passing through other light waves.
 

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Re: Do photons cancel each other out?
« Reply #3 on: 30/03/2014 05:35:50 »

 

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