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Homework Help: Current and photons.

  1. Jan 8, 2007 #1
    I'm ignoring the template because I don't think it's appropiate for the help I want.

    The problem I'm given:
    How many electrons per second strike the target in an X-ray tube operating at a current of 50mA?

    First off, if this is an X-ray tube, where are these electrons coming from, the target? And how why is current for photons measured in amperes? I thought there needed to be charge for there to be current.
  2. jcsd
  3. Jan 8, 2007 #2


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    First off, maybe you should look up "X ray tube". The electrons are accelerated in the tube then hit a target generating the x-rays. That is the current referred to.
  4. Jan 8, 2007 #3


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    An X-ray tube is basically a discharge tube (i.e. a neon or fluorescent light) with a tungsten plate at one end acting as an annode. Electrons travel across a vacuum with high energy and excite tungsten atoms which then emit X-rays when they return to ground level. This question therefore has nothing to do with X-rays but is mainly an electronics question. What relation do you know that links current and charge, and what do you know of the charge on an electron?
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