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Homework Help: Electrons and pressure

  1. Dec 11, 2008 #1
    In a TV, electrons with a speed of 7.31 x 107 m/s strike the screen from behind, causing it to glow. The electrons come to a halt after striking the screen. Each electron has a mass of 9.11 x 10-31 kg, and there are 7.97 x 1016 electrons per second hitting the screen over an area of 2.15 x 10-7 m2. What is the pressure that the electrons exert on the screen?

    Hi, can anyone help me please? I really dont know how to start this question. It confuses me a lot.
  2. jcsd
  3. Dec 11, 2008 #2


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    Homework Helper

    Force is F=m*a. And Pressure is F/A where A is area.

    Force is also dP/dt where P is momentum mv.

    Now you know what the rate of momentum the screen is absorbing by the m*v of the total number of electrons in the stream of electrons in a second. And you know the area over which they want the Pressure.
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