The capacity of a parallel plate capacitor increases with the

The distance between the plates of a parallel plate capacitor is $4 \ mm$ and the potential difference is $60 \ V$. If the distance between the plates is increased to $12 \ mm$,then:

$A$ metal slab of thickness $b = d/2$ is inserted between the plates of a parallel plate capacitor of plate separation $d$. What is the ratio of the new capacitance to the original capacitance?

$A$ capacitor of capacitance $C$ with a distance $d$ between its plates is connected to a battery of $V$ volts. What is the force acting between the two plates?

Five identical metal plates,each of area $A$,are arranged parallel to each other at a constant distance $d$ apart. Plates $1$ and $4$ are connected by a wire,and plates $3$ and $5$ are connected by a wire as shown in the figure. Find the equivalent capacitance of the system between points $A$ and $B$.

In the given system,the area of each plate is $A$ and the distance between two consecutive plates is $d$. What is the charge on plates $1$ and $4$?