The capacitance of a parallel plate capacitor is $12\,\mu F$. If the distance between the plates is doubled and the area is halved,then the new capacitance will be.........$\mu F$.

$A$ capacitor is made of a flat plate of area $A$ and a second plate having a stair-like structure as shown in the figure. If the area of each stair is $\frac{A}{3}$ and the height of each step is $d$,the capacitance of the arrangement is:

Two protons $A$ and $B$ are placed in the space between the plates of a parallel plate capacitor charged up to $V$ volts (see figure). If the forces on the protons are $F_A$ and $F_B$ respectively,then:

$A$ parallel plate capacitor has a plate separation of $2 \ mm$ and is charged by connecting it to a $300 \ V$ battery. What is the energy density in $J/m^3$?

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 $B$.

The insulated plates of a charged parallel plate capacitor (with small separation between the plates) are approaching each other due to electrostatic attraction. Assuming no other force to be operative and no radiation taking place,which of the following graphs approximately shows the variation with time $(t)$ of the potential difference $(V)$ between the plates?