1. The problem statement, all variables and given/known data A spherical conductor of radius 7.00 mm carries a surface charge density of 9.00 μC/mm2. A second hollow, concentric, spherical conductor has an inner radius of 7.09 mm. How much stored energy is there between the spheres? 2. Relevant equations C=Q/V A=4pi(r^2) C=4(pi)(Epsilon_0)((R_a*R_b)/(R_a-R_b)) surface charge density = Q/A U=.5*Q^2/C=.5*C*V^2=.5QV 3. The attempt at a solution I keep getting 2.5o4e^-4 kJ but it isnt one of the answer choices. There is a 250 kJ, but that makes me off by a factor of 1 million... Here are the answer choices: A) 16kJ B) 1000kJ C) 6.4kJ D) 250kJ Thank you very much!