Hello, I've been trying and trying to do this problem for quite a while now, and I can't seem to get an answer which agrees with the book. I figured that one metal sphere would then end up with a charge of 10^13 electrons (so I multiplied that by 1.60x10^-19 to get the charge of all the electrons in the sphere). But there is no charge given for the second sphere! I was using the equation: Nothing seems to work. Even using the same value for q1 and q1 doesn't produce the correct answer, wich the book feels is 0.32 meters. I'm stuck... thanks so much for any help!