# Electric Fields on a Circular Disk

A circular disk has a charge density 0f G C/m^2 and a radius of R m.

A test charge, P, is located Z m above the center of the disk on a line perpendicular to the disk and passing through the center of the disk.

Using polar coordinates (d(area) = r*dr*d(theta)) find the value of the electric field ,E, at P.

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PDF and Word document attached show how to use polar coordinate to find the value of an electric field.

Electric field above surfaces

Electric field above surfaces. See attached file for full problem description.

1. find the electric field a distance z above one end of a straight line segment of length L, which carries a uniform line charge lamda.

check that you formula is constistent with what you would expect for the case z >>L.

2. Find the electric field a distance z above the center of a flat circular disk of radius R, which carreis a uniform surface charge.

What does your formula give in the limit R --> infinity? Also check the ase z >>R.