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Homework Help: Parallel plates

  1. May 31, 2010 #1
    1. The problem statement, all variables and given/known data

    Question Reads:

    An electron enters a parallel plate apparatus 10 cm long and 2.0 wide, moving horizontally at 8.0 10 ^7 m/s. if the potential difference across the plates is 600V, determine

    a) the vertical deflection of the electron from its original path
    b) the velocity with whih it leaves the parallel plate appratus, in both maginitude and direction

    2. Relevant equations,

    v = sqrt ( 2qv / m )

    3. The attempt at a solution

    i have no clue where to start, but i guess this is like a projectile motion ? with gravity applied?
  2. jcsd
  3. May 31, 2010 #2


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    Homework Helper

    Yes it is like projectile motion, except not with gravity.

    If the pd is 600 V and the plates are 2m wide, what is the electric field produced?

    Also if the electric field is the force exerted per unit charge and F=ma, what is the acceleration?
  4. Jun 1, 2010 #3
    you can straight away neglect gravity. calculate & see yourself how small mg is in comparison to qE.

    the elec field is perpendicular to the electron's initial velocity. say electron was initially moving along x & the field is along y.

    now the filed accelerates the electron along y.
    first, find out the time taken for the electron to leave the setup.
    that is just length / vx. (vx = initial velocity. does not change)

    so electron experiences an acceleration along y for this much time. so u can find vy.
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