# Continuous Charge Distributions

## Homework Statement

A charge lies on a string that is stretched along an x axis from x = 0 to x = 3.00 m; the charge density on the string is a uniform 9.00 nC/m. Determine the magnitude of the electric field at x = 8.00 m on the x axis.

## Homework Equations

$\int_0^3 kλ/(8-x)^2\,dx$

## The Attempt at a Solution

k=8.99e9
λ=9

I know k and λ can come out of the integral leaving 1/(8-x^2). which gives me 9.44e-10 which webassign marks wrong.

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vela
Staff Emeritus
Homework Helper
Your set-up looks fine, but I don't get anything close to the numerical answer you're getting.

TSny
Homework Helper
Gold Member

## The Attempt at a Solution

k=8.99e9
λ=9

I know k and λ can come out of the integral leaving 1/(8-x^2). which gives me 9.44e-10 which webassign marks wrong.
Are you thinking about the units for λ?

Problem was the units for λ. Thanks for your help