In reply to John Berry's message of Thu, 15 Feb 2007 11:42:17 +1300: Hi, [snip] >Robin is not right.
Robin was talking about two flat plates. Granted, they only appear as flat plates when close together. The farther apart they are moved, the more they begin to approximate points. > >A metal sphere and a metal cone of equal capacity at an equal voltage and >charge imbalance will have the same net electric field. > >But the electric field density at the point of the cone (along with the >charge imbalance density at that point) is greater than the electric field >density from the sphere which naturally has an even field density. > >In the same way when the sphere is brought near a sphere of opposite charge, >the charge imbalance increases greatly with an equal reduction elsewhere (as >obviously the net charge imbalance isn't changing, nor is the net field) > >This greater charge density in that area increases the electric field >density in that area, not the net field of course. > >I'm wrong about this, anyone got an electrostatic simulation software? >http://www.falstad.com/mathphysics.html <here is some java stuff... > > >On 2/15/07, Harvey Norris <[EMAIL PROTECTED]> wrote: >> >> >> --- Michel Jullian <[EMAIL PROTECTED]> wrote: >> >> > Robin is right, in a parallel plate capacitor >> > C=epsilon*A/d >> > >> > so q (constant here) = C*v = (epsilon*A/d)*v = >> > epsilon*A * v/d >> > >> > so v/d is constant too. >> > >> > Michel >> A tricky thing here was I thought I remebered using >> this formula using English units for d and A. It does >> not give the correct answer then, metric units of cm >> or m must be used for A and d dimensions for the >> formula to be valid. >> HDN >> >> Tesla Research Group; Pioneering the Applications of Interphasal >> Resonances http://groups.yahoo.com/group/teslafy/ >> >> Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition (capitalism) provides the motivation, Cooperation (communism) provides the means.
