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Re: Charged disk; was electrostatic ...

Chuck Britton wrote:

A fairly common misconception is that 'most' of the charge will
collect on the more sharply curved surface, (needle tip). A closer
analysis will indeed show that the charge DENSITY is quite large on
the highly curved surface, but the small area involved does NOT lead
to a preponderance of charge being on the tip. Corona discharge has
been ruled out in this discussion of an 'isolated' object. Lightning
rod tips are NOT isolated and do indeed exhibit coronal discharge.

I am willing to accept this. If this is true then the cylinder
approximation (with three well defined surfaces) makes
sense to me.

Can somebody answer this question? Suppose the electrified
object is like a pear. Or more exactly it is a set of two spherical
segments connected smoothly with a truncated cone. Let the
left segment have R1=20 cm, the right segment R2=5 cm and
the distance between the centers of segments 30 cm. There is
nothing special about this geometry; it is an illustration.

We all known that concentration of charges will be higher on
the right "pole" than on the left "pole". But how many times
larger? Factor of 4? Factor of 16? Neither of the above? Is
there any rule of thumb about this?
Ludwik Kowalski