Plate with slits, on rollers, a la Feynman In one of Feynan's lectures, he describes a thought experiment about trying to 'beat' the uncertainty principle. Without going into all the details, this version of the two-slit experiment has the diffracting plate mounted on rollers. The text and the figure seem to imply that when an electron passes through a slit and is deflected downwards, the plate will acquire an upward momentum. If the electron travels upwards, the plate will recoil downwards. Now, is this literally true, or is it just a pedagogic device that Feynman has used to make a specific point? Is there really a collision and an exchange of momentum when an individual electron deflects while passing through a slit? Another question (one that I found, unanswered, somewhere on the web) : When an electron is diffracted at a slit, and there is acceleration in the upward or downward direction ... should we not expect EM radiation due to the accelerating charge?