Two parallel plate capacitors of capacitance $C$ and $2C$ are connected in parallel and charged to a potential difference $V$ by the battery. The battery is then disconnected and the space between the plates of capacitor of capacitance $C$ is completely filled with a material of dielectric constant $K$. The potential difference across the capacitors now becomes

A parallel plate capacitor of capacitance C is connected to a battery and is charged to a potential difference V. Another capacitor of capacitance 2C is similarly charged to a potential difference 2V. The charging battery is now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is:

For the circuit shown in figure, which of the following statements is true ?

Consider the situation shown in the figure. The capacitor $A$ has a charge $q$ on it whereas $B$ is uncharged. The charge appearing on the capacitor $B$ a long time after the switch is closed is

Two identical capacitors have the same capacitance $C .$ The negative ends of the capacitors are connected together. One of them is charged to potential $V_1$ and the other $V_2$. When the positive ends are also connected, the decreases in energy of the combined system is

Four metal plates numbered $1,2,3$ and 4 are arranged as shown in Figure.The area of each plate is $A$ and the separation between adjacent plate is $d$. The capacitance of the arrangement is