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Q & A: screened electrical forces

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Most recent answer: 07/03/2009
Q:
Sir.What is force between two charged rods when a copper plate is placed in between them.I mean whether the force increases or decreases than the before value or becomes zero.And why..What happens when a glass rod is placed instead of copper plate...
- Prudhvi Raj Borra (age 16)
Machilipatnam,Andhra,India.
A:
When the rods are very far apart, compared to the thickness of the plate, the plate has almost no effect on the potential energy. When the rods almost touch the plate, it allows charge to rearrange so as to substantial lower the potential energy. Thus the plate increases the difference between the high potential energy of the far-apart rods and the low potential energy of the close-together rods. Therefore it increases the integral of the force from one position to the other. I'll make an educated guess here, that it increases the force at every particular separation.

The dielectric should do the same thing, to a lesser degree. 

Mike W.

(published on 07/03/2009)

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