In cathode ray tube electrons hit a fluorescent screen. Then photons are emitted. But where did electrons go after they hit the screen?

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    $\begingroup$ Into the screen material, then to ground. The photons come from energy deposited by the electron as it is slowed to a stop in the screen. $\endgroup$ – Jon Custer Dec 8 '18 at 20:41
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    $\begingroup$ There is a grid at the front of the screen that collects electrons, and keeps the screen from building up a large negative charge. These electrons are pulled away from the screen by associated circuitry. $\endgroup$ – David White Dec 8 '18 at 22:41
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    $\begingroup$ Conservation of charge forbids the conversion of an electron into a photon. $\endgroup$ – Ben Crowell Dec 8 '18 at 23:21
  • $\begingroup$ @BenCrowell Why not present that as an answer. $\endgroup$ – Bob D Dec 9 '18 at 21:19
  • $\begingroup$ You can run your hand past the front of a recently turned off CRT and feel the static electricity. $\endgroup$ – immibis Dec 10 '18 at 1:26

The way that these cathode ray tubes work is through the attraction of negative electrons to the positive anode. The focussing anode accelerator accelerates the electrons to the phosphor in which the incident energy is absorbed and then transferred to the photons which emit the beams of light. function of cathode ray

The electrons themselves are absorbed into the phosphor screen. Residual electrons scatter randomly and eventually end up but collected again by the anode and sent back to the circuits electrical ground.


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