A parallel plate air capacitor of capacitance `C` is connected to a cell of `emF V` and then disconnected from it. A dielectric slab of dielectric constant `K`, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect ?

Options

A. The energy stored in the capacitor decreases k times
B. The change in energy stored is `1/2 CV^2 (1/k-1)`
C. The charge on the capacitor is not conserved
D. The potential difference between the plates decreases k times

Answer

C

Explanation

As the capacitor is isolated so charge will remain conserved.