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**1. The problem statement, all variables and given/known data**

A charge (uniform linear density = 9.4 nC/m) lies on a string that is stretched along an x axis from x = 0 to x = 3.0 m. Determine the magnitude of the electric field at x = 5.5 m on the x axis.

**2. Relevant equations**

[tex]\stackrel{\rightarrow}{dE}=\frac{\lambda dx}{4 \pi \epsilon_{0} r^2}\hat{r}[/tex]

**3. The attempt at a solution**

I believe the unit vector can eliminated since the point is on the same axis as the line of charge (cos(0)=1). My concern is with my limits of integration and with my "r" argument. My final expression was:

[tex]E = \frac{\lambda}{4 \pi \epsilon_{0} 5.5^2} \int^{3}_{0} dx[/tex] which got me an 8.38244 N/C, a wrong answer.