What does an electric dipole experience when placed in a uniform electric field?

Two point masses,each of mass $m$ and charges $+q$ and $-q$,are attached to the ends of a massless rod of length $L$. This assembly is placed in a uniform electric field of intensity $E$ at a small angle $\theta$ with the field. How much time will it take for the rod to become parallel to the electric field?

An electric dipole is situated in an electric field of uniform intensity $E$ whose dipole moment is $p$ and moment of inertia is $I$. If the dipole is displaced slightly from the equilibrium position,then the angular frequency of its oscillations is

Three identical dipoles are arranged as shown below. What will be the net electric field at $M$?

An electric dipole with dipole moment $2 \times 10^{-10} \text{ C m}$ is aligned at an angle $30^{\circ}$ with the direction of a uniform electric field of $10^4 \text{ N C}^{-1}$. The magnitude of the torque acting on the dipole is:

Two point charges $+q$ and $-q$ are held fixed at $(-d, 0)$ and $(+d, 0)$ respectively of an $(x, y)$ coordinate system. Then: