Physics Help Forum parallel plates

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum

 Aug 30th 2009, 07:17 PM #1 Junior Member   Join Date: Jul 2009 Posts: 9 parallel plates I dont know where to begin with these one could somebody help me with it Two large, parallel metal plates carry opposite charges of equal magnitude. theyh are separated by 45mm and the potential difference between them is 360 volts. a) what is the magnitude of the electric field (assumed to be uniform) in the region between the plates? b) what is the magnitude of the force this field exerts on a particle with charge +2.40 nC? c) use the results of part b) to compute the work done by the field on the particle as it moves from the higher potential plate to the lower? hoping for a reply thanks...
 Aug 30th 2009, 08:54 PM #2 Senior Member   Join Date: Apr 2008 Location: HK Posts: 886 OK, you don't know how to start. Let me remind you of some equations for parallel plates. $\displaystyle V=Ed$ V is the potential difference across the parallel plates E is the electric field strength d is the separation between the plates $\displaystyle F=Eq$ F is the force experienced by a unit test charge E is the electric field strength q should be the charge These problems are typical questions, you should find more examples in text books. In case you haven't learnt about the topic, this question may be a bit difficult with equations not known.
 Aug 30th 2009, 09:43 PM #3 Junior Member   Join Date: Jul 2009 Posts: 9 oh ok thanks but what about the plates their do they have any effect about the problem?
Aug 31st 2009, 10:07 PM   #4
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Join Date: Apr 2008
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Posts: 886
I don't quite understand what you mean
 what about the plates their do they have any effect about the problem?
For parallel plates, the electric field lines inside are parallel to each other which is very different from the field lines of a charged sphere which may be diverging. If the electric field is not constant, you cannot use the equations mentioned

 Aug 31st 2009, 10:23 PM #5 Junior Member   Join Date: Jul 2009 Posts: 9 thanks you do answered my question though

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