Two circular parallel plate capacitors lie next to one another. Both capacitors have the same dielectric material between the plates, and the same distance between the plates. The energy stored in capacitor 1 is twice that of capacitor 2. The voltage across capacitor 2 is 2 times that of capacitor 1. What is the ratio of the radius of the plates of capacitor 1 plates to the radius of capacitor 2’s plates?