A 9 nF parallel-plate air capacitor is fully charged by a 12 V battery. The voltage between the plates is measured to be V1, and the stored potential energy is measured to be PE1. While the battery remains connected, a dielectric with dielectric constant K = 6 is placed between the plates. The resulting voltage between the plates is then measured to be V2, and the stored potential energy is measured to be PE2. Which one of the following statements is true? Group of answer choices V2 = V1 and PE2 = (2/3) . PE1 V2 = V1 and PE2 = 18 . PE1 V2 = (1/6) . V1 and PE2 = (1/36) . PE1 V2 = V1 and PE2 = 6 . PE1 V2 = (1/6) . V1 and PE2 = (1/12) . PE1 V2 = (1/6) . V1 and PE2 = PE1 V2 = (1/6) . V1 and PE2 = (1/72) . PE1 V2 = V1 and PE2 = 3 . PE1