Electric flux trough an infinite plane 2

[julius71989]

Sorry, what I posted earlier was wrong.. here is the question:

an charge Q is at the origin. Find the electric flux an infinite plane at z distance from z axis.

Please check my attempts to the solution. Please check what's wrong in it because until now I am not getting the correct answer.. thanks a lot. click the link below:

figure: http://pic40.picturetrail.com/VOL359/11337670/20318718/330158477.jpg
solution: http://pic40.picturetrail.com/VOL359/11337670/20318718/330158480.jpg

 

[Dick]

Man! That is REALLY hard to read. I usually don't pester people about using TeX, but that's pretty bad. The sheer font wackiness is awful. I think you are forgetting that dS=2*pi*r*dr. Note the r. I'd be more sure, but I can't look at that jpg again. It hurts my eyes. :)

 

[Defennder]

You don't have to integrate it to find the flux. Think in terms of Gauss law and electric field lines and you can avoid all the maths.