Problem: A parallel-plate capacitor has square plates that are 7.00cm on each side and 4.10mm apart. The space between the plates is completely filled with two square slabs of dielectric, each 7.00cm on a side and 2.05mm thick. One slab is pyrex glass and the other is polystyrene.
Part A: If the potential difference between the plates is 73.0V, how much electrical energy is stored in the capacitor?
I need help to find how much electrical energy is stored in the capacitor.