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Mar29-12, 04:13 PM
Drakkith's Avatar
P: 11,884
Quote Quote by lostprophets View Post
i,d like to ask a simple question please.
did or has anyone every checked the first screen with the slit in it (the single slit screen not the double one and not the screen the photon hits at the back) to see if there is any sign either side of the slit, that a photon has past through it?

many thanks
If you detect the photon BEFORE the slit, then the photon never passed through it. If you detect the photon AFTER the slit, then the photon went through it. A photon cannot be detected before the slit AND pass through it, as it has already been detected.