An electric dipole is placed in a non-uniform electric field,then . . . . . . .

$A$ system of three charges is placed as shown in the figure. If $D >> d$,the potential energy of the system is best given by:

Out of the following molecules,which one represents a polar molecule?

When does the torque acting on an electric dipole in a uniform electric field become zero?

$A$ point charge $q$ of mass $m$ is suspended vertically by a string of length $l$. $A$ point dipole of dipole moment $\overrightarrow{ p }$ is now brought towards $q$ from infinity so that the charge moves away. The final equilibrium position of the system including the direction of the dipole,the angles and distances is shown in the figure. If the work done in bringing the dipole to this position is $N \times (mgh)$,where $g$ is the acceleration due to gravity,then the value of $N$ is. . . . . . (Note that for three coplanar forces keeping a point mass in equilibrium,$\frac{F}{\sin \theta}$ is the same for all forces,where $F$ is any one of the forces and $\theta$ is the angle between the other two forces)

Determine the electric dipole moment of the system of three charges,placed on the vertices of an equilateral triangle,as shown in the figure.