As I read my own message I see that one important point
about the radial distribution of Q should be emphasized.
The numbers presented were surface charge densities.
What follows are fractional charge associated with
different distances from the axis of the disk. To get
fractional charges I multiplied sigmas by the areas.
cal # r(m) % of total Q
0 0.00000 0.5
1 0.02771 3.5
2 0.05524 7.4
3 0.08313 12.3
4 0.11084 19.5
5 0.13855 56.7 (includes the side)
Thus more that 50% of the total charge is associated with
the outermost segment of the disk. (The disk consists of six
segments: five hollow cylinders, inside of each other, and
one non-hollow cylinder near the axis. Each segment, except
the last, has two surfaces, top and bottom. The last, the
outermost segment, has three surfaces: the top, the bottom
and the side. The table below shows sigmas; these are the
same numbers which were posted earlier today.
r (m) my sigmas (pC/m^2) at 100 volts
--------------------------------------
0.00000 7673 <-- central segment
0.02771 7797 <-- ring #1
0.05542 8227 <-- ring #2
0.08313 9106 <-- ring #3
0.11084 10826 <-- ring #4
0.13855 14458 <-- ring #5
9716 <-- side of #5
Ludwik Kowalski