Disk and Electric Field's Direction

[Soaring Crane]

Homework Statement

A thin disk with a circular hole at its center, called an annulus, has inner radius R1 and outer radius R2. The disk has a uniform positive surface charge density omega on its surface.

Figure's link: http://i131.photobucket.com/albums/p289/SoaringCrane/yf_Figure_21_421.jpg

Find the direction of the electric field E. Consider points above the annulus in the figure.

Homework Equations

This part of the question is really conceptual.

The Attempt at a Solution

Since the disk's overall charge is positive, the force of a positive test charge above the annulus would be directed away from the hole. Therefore, the electric field's direction would be in the positive x-direction??

Thanks.

 

[Kurdt]

You are correct but can you show it using a vector diagram?