It’s been a while since I posted a question in the Cute Physics Problems folder so I thought I’d offer this one. It’s not particularly hard, but I think it’s quite instructive.
A thin spherical shell of radius r carrying a charge Q spread uniformly with constant surface density is split into two equal halves by a narrow planar cut passing through the centre as shown in the detailed diagram below:
Calculate the force arising from electrostatic repulsion between the two hemispherical shells, expressing your answer in terms of Q and r in SI units.
Answers through the Comments Box please. First correct answer wins a tomato*
*subject to availability
In the Dark 