When is the torque on an electric dipole in an electric field maximum?

An electric dipole consisting of two opposite charges of $2 \times 10^{-6} \ C$ separated by a distance of $3 \ cm$ is placed in an electric field of $2 \times 10^5 \ N/C$. The maximum torque on the dipole will be

For an electric dipole, if the magnitude of each charge is $10^{-10} \, \text{stC}$ and the distance between them is $1 \, \mathring{A}$, then the dipole moment is:

The unit of electric dipole moment is ......... .

Three identical small electric dipoles are arranged parallel to each other at equal separation $a$ as shown in the figure. Their total interaction energy is $U$. Now,one of the end dipoles is gradually reversed. How much work is done by the electric forces?

One end of a spring of negligible unstretched length and spring constant $k$ is fixed at the origin $(0,0)$. $A$ point particle of mass $m$ carrying a positive charge $q$ is attached at its other end. The entire system is kept on a smooth horizontal surface. When a point dipole $\overrightarrow{p}$ pointing towards the charge $q$ is fixed at the origin,the spring gets stretched to a length $\ell$ and attains a new equilibrium position. If the point mass is now displaced slightly by $\Delta \ell \ll \ell$ from its equilibrium position and released,it is found to oscillate at frequency $\frac{1}{\delta} \sqrt{\frac{k}{m}}$. The value of $\delta$ is. . . . . .