electromagnetism

Question

A 4uC linear charge is distributed in a square of side 0.7m, which is contained in the 'yz' plane and has its center at the origin. The 'x' axis passes through the center of the square. Find the electric field on the 'x' axis, at a distance of 10 m.

Answer 1

10 m is much larger than .7 m, so the electric field will be approximately

E ~ (1/ 4π ε0) 4E-6 / 10^2 ~ 360 V/m

The exact answer involves integration over y and z. I don't think the integrals can be done in closed form. I was able to reduce the form to an integral over y which I used a TI calculator to evaluated at x = 10 , and got an answer within 1% of 360 V/m