From: John Denker <jsd@av8n.com>
To: Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, 1 December 2011 2:00 AM
Subject: Re: [Phys-l] [Electric potential of charged spheres
Work is done against repulsion when we bring the together and work is
done by the charges when you seperate them. Should we not take these
also into account
Note: In this step (and all other steps), total charge remains
constant. In all steps /except/ this one, the charge on each sphere
remains constant.
3) Bring them together again. In so doing, you do work against
their mutual electrostatic repulsion. That is to say, the energy
of the system goes up.
4) Voltage is energy per unit charge. The energy went up, so the
voltage went up. The new voltage /must/ be greater than 5V.
==================
On 11/29/2011 03:08 PM, Paul Nord wrote:
1) Start with the original situation, v=1V and v=9V, spheres far apart.
2) Bring them together long enough to symmetrize the charge, then
move them back to their original positions. v=5V and v=5V now.