Hi, I'm having trouble with a problem that I'm doing in my electricity and magnetism class. I can't even understand what it's asking and what the picture looks like. Here is the problem: In an electron microscope, a beam of energetic electrons, originally accelerated through a potential of Vo (which is typically a few thousand volts), passes a thin charged long wire stretched at right angles to the original beam. Assume the line charge density is lambda, and that the beam is slightly deflected by the wire. Show that the angular deflection of the beam from its original path is independent of the distance of the electron beam from the wire (i.e.: independent of "impact parameter"). Such an arrangement is called an "electron-optic biprism" since electrons passing on opposite sides of the wire are oppositely and equally deflected. [Hint: Assume to first approximation that the beam velocity in the forward direction is unaffected. Find the transverse velocity.] If anyone can explain this phenomenon to me, that would be great. Thanks.