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Re: Charge Distribution around pointed areas



I've tried explaining to the students qualitatively.

Point charges reside on the surface and they will repel one another, so they
will stay as far apart as possible. If the conductor is a sphere, the
charges will then be uniformly spread out, i.e. at equal distance from each
other.
If the sphere is made geometrically pointed at one end, you may now ask the
kids to consider those charges at both ends. On the end of the rounded end,
the forces between the charges is mostly exerted through air, so the
distance between them will be about equal. But as we move to the sharp end,
the charges near the extreme end of the sharp corner (visualise one charge
above and one below) are repelled through a different medium, i.e. that of
the conductor rather that air. Hence the force exerted on each other is
less, and these charges can be then closer together. Eventually, it's about
'force' balancing. Drawing on the board will allow the students to
understand much better.
Feel free to criticise if the above visualisation method is flawed.

Rom