1. The problem statement, all variables and given/known data It's told me to treat two charged concentric sphere's as parallel plates with Q=5nC on one, and -Q on the other (both with uniform spread). The distance between them is 5mm, and the surface area of each plate/sphere is 0.13m2. Calculate the energy stored in the electric field between the plates? 2. Relevant equations Obviously, parallel plates can use the equation E=Vd because there's an uniform electric field, but I don't know E or V so that equation is as good as useless. Do you think it expects me to manipulate capacitance equations to work out the answer? Because they are infact charged sphere's, can I use equations which use the inverse square law in them? Or do i have to stick to the fact they are now parallel plates? 3. The attempt at a solution So there's a uniform electric field, but I don't really understand what it means by energy within the electric field? The following question is asking me to work out the total energy stored if this setup were a capacitor (which is easy enough, using Q=CV etc.), but not sure what equations to use if were looking at a normal uniform electric fields question?