# Electric field calculation

## Homework Statement

let say we have a positively charged rod with length L then what is the electrical field at the middle point of the rod

## The Attempt at a Solution

I put the origin at the middle point
so dE=Kdq/r^2, dq = Q/L dx
E= kQ/L integral from -L/2 to L/2 (1/x^2)dx
=-KQ/L[2/L +2/L] =KQ/L (4/L) =-4KQ/L^2

well I expected it to be zero and it wasn't so should it be if so then what did I do wrong?

The electric field is defined as $$\mathbf{E} = \displaystyle \lim_{q_0 \to 0} \frac{\mathbf{F}}{q_0}$$.