A parallel plate capacitor with C = 0.6 µF is charged with a potential difference of 100V and then isolated. Let's say the plates are vertical and the capacitor is partially immersed in a bucket filled with a liquid. The liquid has dielectric constant k = 25 and fills' uniformly the volume of the capacitor for 1/3. Calculate the variation of the energy of the capacitor.

A parallel plate capacitor with C = 0.6 µF is charged with a potential difference of 100V and then isolated. Let's say the plates are vertical and the capacitor is partially immersed in a bucket filled with a liquid. The liquid has dielectric constant k = 25 and fills' uniformly the volume of the capacitor for 1/3. Calculate the variation of the energy of the capacitor.