1. The problem statement, all variables and given/known data Determine the electrostatic energy, W, of a spherical shell of radius R with total charge q, uniformly distributed. Compute it with the following methods: a) Calculate the potential V in spherical shell and calculate the energy with the equation: W = (1/2) * ∫σVda b) Calculate the electric field inside and outside, and calculate the energy with the equation: W = (1/2) *εo ∫ E^2 dV 3. The attempt at a solution a) Electric filed inside = 0 Electric field outside = (1/4piεo) * Q/r^2 The Potential is v(r)-v(infinity) = - ∫(infinity to R) (Electric field outside) dr = (1/4piεo) * Q/R W = (1/2) * ∫σVda because dq = σda W = (1/2) * ∫(1/4piεo) * q/R * dq = (1/8piεo) * Q^2/R b) The electric field is already calculated... W = (1/2) *εo ∫ E^2 dV = (1/2) *εo ∫ (1/16pi^2εo^2) * q^2/r^4 dV (1/2) *εo ∫(0 to 2pi) ∫(0 to pi) ∫ (0 to R ) [(1/16pi^2εo^2) * q^2/r^4 ] * r^2 sinθ dr dθ dβ = -(1/8piεo) * Q^2/R The problem is, the difference in the signal...isn't it supposed to be equal??