Find Potential, Grounded Infinite Plate and a Dipole

[Formslip]

Homework Statement

[PLAIN]http://img846.imageshack.us/img846/1269/img029z.jpg



2. The attempt at a solution

My attempt and relevant equation is only there in the picture. I know how to find the electric field of an infinite plane np, gaussian pillbox etc.
im not sure what role the dipole plays, and I am not sure why exactly the plate is grounded.

my teacher sort of reads straight from the textbook, so its hard to pick this stuff up in class.
If you could just point me in the right direction to answer this question i would much appreciate it.

 

[ideasrule]

Are you sure you know how to field the electric field of an infinite plane? The easiest way is to use the mirror charge method. Since a dipole is just two closely spaced charges, you can use the same method to solve this problem.

 

[Formslip]

ah yes turns out that is how you do it. using the same method as if it was a point charge, but instead using the potential for an electric dipole.

so the answer comes out looking like:

http://img823.imageshack.us/img823/279/picture006mv.jpg the way i worked it out, that seems right but i think i overheard someone in my class talking about that bottom part being to the power of 3/2. anyway, I am pretty confident in my answer since it follows all the same boundary conditions and everything.

thanks for the response

 

[ideasrule]

Yes, that's correct. It shouldn't be a power of 3/2.

 

[kloptok]

Some speculation concerning the 3/2:

In the case of a point charge the potential V(r) is proportional to 1/r for the potential, or in cartesian coordinates 1/(x²+y²+z²)^(1/2). When differentiating to find the electric field, this becomes proportional to 1/(x²+y²+z²)^(3/2). This could be where that 3/2 comes from.

Your answer seems correct however.