The energy required to charge a capacitor is: W = ½εrCV2 From this we see that a capacitor with a linear dielectric in between its plates requires a bigger energy to charge up to a given potential. My question is: Should this be intuitive? My teacher said that it is because the parts of the electric field is cancelled off by the bound charges. I guess I can understand that since you then have to pull in more charge overall. However - wont these charges being pulled in also experience a weaker repulsion due to the cancelled off charges?