# Electric field caused by a uniform linear charge

1. Dec 2, 2008

### gotem3303

A uniform linear charge density of $$\lambda$$ = 2.0 nC/m is distributed along the x-axis from x = 0 to x =3m. Which integral is correct for the magnitude of the electric field at x = -4 m on the x axis?

I'm going over a old test and he didn't circle the correct answer but I'm trying to understand the denominator.

I'm pretty sure I have everything but the denominator, would it be $$\int$$$$\frac{18dx}{(4+x)^{2}}$$ from 0 to 3?

2. Dec 2, 2008

### Redbelly98

Staff Emeritus
Looks okay, except that you did not write any of the units.