1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution so plugging in the variables, the density should be 0.002 with density known, and the volume of the sphere with radius 10, we can find the mass. (density x volume = mass) mass is about 16.75 kg it states the amount of charge is symmetric so I assume the number of protons equals to number of electrons. dividing the mass 16.75 kg by mass of a proton + electron (1.623 x10^-27 kg + 9.11 x 10^-31) = 1.03 x 10^28 pairs of proton and electron each pair has charge 2q then, so 1.03 x 10^28 x 2(1.602 x10^-19 C) = 3.3 x 10^9 C in the sphere with radius 10. Is this correct?