I'm having trouble answering these questions and i was curious to see how other would answer them: If the potential at a point is zero, must the electric field also be zero? (No) Give an example. How does the energy stored in a capacitor change when a dielectric is inserted if (a) the capacitor is isolated so Q doesn't change, (b) the capacitor remains connected to a battery so V doesn't change. If there is a point along the line joining two equal positive charges where the electric field is zero? Where the electric potential is zero? Explain.