# Electric flux theory.

1. Jan 30, 2013

https://www.smartphysics.com/Content/Media/Images/EM/03/h3_lineD.png [Broken]

In the image above, i was asked to find the electric field at point P. since the y-components cancel due to symmetry, i used he equation $\Phi$=$\int$E dA=Qenclosed/$\epsilon$ .

I found q1 and q2 by multiplying (charge density x h). then from that, i added the charges up to get Q(enclosed). I found my E by $\Phi$/(2πah).
This method was wrong apparently but i don't know why. can someone explain?
Is it because the electric field through the surface is not uniform?

Last edited by a moderator: May 6, 2017
2. Jan 30, 2013

### Staff: Mentor

Exactly.

3. Jan 30, 2013