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Please help with this electric potential problem

  • Thread starter kevinf
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  • #1
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Homework Statement



One conductor of an overhead electric transmission line is a long aluminum wire 2.40 cm in radius. Suppose that at a particular moment it carries charge per length 1.40 µC/m and is at potential 350 kV. Find the potential 10.9 m below the wire. Ignore the other conductors of the transmission line and assume the electric field is everywhere purely radial.

Homework Equations



i think for this problem you would use the integral of dq/r right?

The Attempt at a Solution



i am not sure how to do this problem. it tells me that it is 10.9 m below the line but it doesn't say where under the wire. would i some how use the 350 kV and get the location under the wire? also i am not sure how the radius of the wire comes in the equation. the ones that i have been doing are rods that have no radius so i am not really sure how to do this problem
 

Answers and Replies

  • #2
Redbelly98
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Does your textbook or course notes discuss the electric field of a line charge? That would be relevant here.
 
  • #3
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yes but the example that they gave is much simpler and it is just a rod with no radius
 
  • #4
Redbelly98
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Okay, good.

The same expression for electric field will be true here, as long as:
  • The distance is taken to the center axis of the transmission line
  • The distance is larger than the radius of the transmission line
(Inside the transmission line, E=0 as for any conductor)
 
  • #5
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oh sorry this is asking for electrical potential though
 
  • #6
Redbelly98
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Potential and electric field are related via doing an integral.
 

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