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Homework Help: Please help, particle accelerated through potential

  1. Mar 13, 2010 #1
    1. The problem statement, all variables and given/known data
    A charged particle is accelerated through a potential of 15000 volts, after which it passes between two (parallel)deflecting plates. What voltage must be applied to these plates to deflect the particle an angle of 10 degrees.

    0.5 cm between plates, plates are 3 cm long, 10 degrees below horizontal axis, particle intially starts of on the horizontal axis heading into the plates

    2. Relevant equations
    I am confused on how you would relate the potential the particle is accelerated through to its velocity. What happens to a particle that passes through a potential, and how does the properties of the potential speed up or slow down the particle.

    3. The attempt at a solution
    Since im confused about the initial information I dont even have an attempt yet, Im assuming you might need to use the work energy conservation theorem at some point but why
  2. jcsd
  3. Mar 13, 2010 #2
    A charged particle in an electric field feels a force F = qE. Which can be related to F=ma, so you see it will accelerate. Well a change in potential leads to an electric field, so the particle will accelerate (if a positive charge) from a high potential to a low potential.

    If you remember the potential is related to the electric potential energy by, EPE = qV. So using conservation of energy, you can find the final velocity knowing the change in potential the particle travels through and its initial velocity.
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