A parallel-plate capacitor containing a dielectric slab of relative permittivity εr=6.0\varepsilon_r = 6.0εr=6.0 is connected to a constant voltage source. The energy stored in the capacitor is EEE.
The capacitor is then disconnected from the voltage source, and the dielectric slab is completely removed. Additionally, the separation between the plates is halved.
What is the energy now stored in the capacitor?
13E\frac{1}{3}E31E
1.5E1.5E1.5E
3E3E3E
12E12E12E
