1. The problem statement, all variables and given/known data The electric field at the surface of a charged, solid, copper sphere with radius 0.19m is 2800 N/C , directed toward the center of the sphere. What is the potential at the center of the sphere, if we take the potential to be zero infinitely far from the sphere? 2. Relevant equations 3. The attempt at a solution Ok, so I got the correct answer, but missed the sign. What I did was: I know that the electric field is 3800 N/C at the surface, and I know the radius, so I calculated the electric flux through the sphere. I found the flux to be 1723.85 Vm. Then, I solved for Q_enc and found it to be 1.526*10^-8 C. Then, I used the equation V = 1/(4pi\epsilon_0)*∫dq/r to find that the potential is 722V. My question: The question states that the electric field points to the center of the sphere, implying the charge enclosed is negative. Is this why the potential is negative?