# Electric Potential

A nonuniform linear charge distribution given by $\lambda = bx$, where $b$ is a constant, is located along an $x$ axis from $x = 0$ to $x = L$. What is the electric potential at a point on the $y$ axis? Set potential equal to zero at infinity. Express your answer in terms of the variables given and $\epsilon_0$ (epsilon not).

I have calculated the answer to be: $$b\frac{\sqrt{L^2 + y^2} - y}{4\pi\epsilon_0}.$$ The site I enter this answer onto tells me I am wrong. I have checked this with my dad, who is very good at physics, and he agrees with me on this answer. I would like to know if this answer is correct, and if not, why. Thanks.

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The potential should be symmetric about $x$-axis, (interchange $y\rightarrow-y$), so you did something wrong. On closer look that is the only error. Change $y$ to $\sqrt{y^2}$