1. The problem statement, all variables and given/known data Two 10-cm-diameter metal disks separated by a 0.64-mm-thick piece of Pyrex glass are charged to a potential difference of 1100 V . What is the surface charge density on the disks? What is the surface charge density on the glass? 2. Relevant equations C=(e_0A)/d C=Q/V charge density=Q/A 3. The attempt at a solution Q/V=(e_0A)/d) Q=((e_0A)/d)*V charge density= ((e_0A)/d)*V)/A charge density=(((8.85*10^-12)(pi*.05^2)*1100/.00064)/(pi*.05^2) I have also tried multiplying the dielectric constant for pyrex (google gave me 4.7) by e_0 and nothing has worked. I am not sure what the difference between the surface charge density on the glass vs. the disks would be, or how to find it.