- #1
vs5813
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Homework Statement
Using Gauss' law, or otherwise, find an expression for electric potential at a distance r from an infinitely long straight line of charge of length h with linear charge density lambda per unit length.
Homework Equations
q=lambda*h
The Attempt at a Solution
The first part is easy, using gauss' law to find electric field..the result i get is
E=lambda/(2*pi*r*epsilon_0)
..which should be correct. But then I'm not sure how to find potential in this case. I tried using the equation:
E= - grad*V
so
V = integral[E*dl]
V= -lambda/(2*pi*epsilon_0) integral_from_infinity_to_r[(1/r) dr]
..which leads me to:
V = -lambda/(2*pi*epsilon_0) [ln(r)]
where the ln(r) is evaluated from infinity to r...and I am not sure that looks right, or where to go from there.. I don't know what the solution is supposed to be and I couldn't find any explanations when i googled it..anyone have any idea? :uhh: thankyou sooo much!