Electric Charge from a ring?

1. Sep 2, 2005

In a uniformly charged ring of radius r, if there is an imaginary line from the center of the ring extending outward
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At the center of the ring Im told the charges cancel so the net charge is zero. And at infinity, the charge is so small it approaches zero.

Going out from the ring, there is some point X where the charge is greatest.

Why does this effect take place? How to figure out the field energy lines that have an effect on point X?

tia

2. Sep 2, 2005

mukundpa

I think you have to determine maximum Elecric field on the axis of the ring

3. Sep 2, 2005

Kazza_765

You can work this out just using coulombs law. Work out the force on a particle at a distance s due to an infinitismal point of the ring and then integrate around the ring. If you do it right you'll get.
$$E=K\frac{qz}{(z^2+R^2)^\frac{3}{2}}$$
where q is the total charge on the ring and z is the distance along the perpendicular axis.
I don't think this really answers your question but perhaps if you plot it, it might be of some help. It at least explains why there is a point where the electric field is at a maximum.