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Charge Density (rod)

  • #1
198
0
Never mind, i got it, whew



Homework Statement


http://img137.imageshack.us/img137/6250/chargqg0.th.jpg [Broken]
The rod has a nonuniform charge density lambda = ax (a is a positive constant). Find electric potential at point A.

Homework Equations


V = kq/r
E = kqq/r^2
V = -[tex] \[ \int_a^b E dot dr\] [/tex]

The Attempt at a Solution


I am pretty close to the answer, I'm just not quite there.
If I'm not mistaken it is something like:
[tex] \[ \int_d^{L+d} kax*r/r^2\,dr [/tex]
but I'm not quite sure what to do with the 'x', from the answer, I know that it has to end up being the integral of 1/r, so x can't be r because it would end up being just the integral of dr

Maybe the limits are incorrect?
 
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Answers and Replies

  • #2
4
0
Hi! I have a similar problem...

A rod of length L lies along the y-axis with its center at the origin. The rod has a nonuniform linear charge density lambda =a | y | , where a is a constant with the units {\rm C}/{\rm m}^{2} . Determine the constant a in terms of L and the rod's total charge Q.

I know that for uniform charge its lambda=L*Q and then integrate but what do I do in this case?

Thanks!
 

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