Electrical Potential Difference between two plates

AI Thread Summary
To find the potential difference between two charged plates with a stationary particle, the gravitational force acting on the particle must equal the electric force. The gravitational force is calculated using Fg = mg, while the electric force is given by Fe = qE. The potential energy (PE) can be derived from the height of the particle between the plates, leading to the equation PE = mgh. The potential difference (V) is then calculated using V = PE/q. The initial calculations presented suggest a misunderstanding, as the resulting voltage appears excessively high, indicating a need for reevaluation of the approach.
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Homework Statement


HELP!
A charged particle is stationary between two horizontal charged plates. The plates are 2.0 cm apart. The particle has a mass of 4.0X10^-13 kg and a charge of 2.4 X 10^-18 C. Find the potential difference between the plates.


Homework Equations



V= EPE/q ?
...except I have no idea how to find the potential energy. Also, I have no clue how the mass given in the problem fits into an equation.

The Attempt at a Solution


I need someone to help me start this!

 
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Looks like a force-balance problem. The force of gravity (down) on the particle is balanced by an equal electric force (up). Begin with Fg = Fe and fill in the detailed formulas before solving for what you want.
 
So is this how I would do it?:
PE=mgh
PE=(4.0x10^-13)(9.8m/s/s)(1.0cm)
PE=3.92x10^-12

V= EPE/q
V=3.92x10^-12/2.4x10_18C
V= 6.8x10^23V
I don't think I did it right...
 
Fg = Fe
mg = qE
 
Thank you :]
 

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