We have a parallel-plate capacitor, with each plate having a width W and a length L. The plates are separated by air with a distance d. Assume that L and W are both much larger than d. The maximum voltage that can be applied is limited to Vmax = Kd, in which K is called the breakdown strength of the dielectric. Derive an expression for the maximum energy that can be stored in the capacitor in terms of K and the volume of the dielectric. If we want to store the maximum energy per unit volume, does it matter what values are chosen for L, W, and d? What parameters are important?