An electron and a proton are at a distance of $1\,\mathring{A}$. The dipole moment of this system will be in $(C \cdot m)$:

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

An electric dipole is placed in a non-uniform electric field. It may experience:

Two charged particles each of mass $9.8 \text{ g}$ and charges $+20 \mu\text{C}$ and $-20 \mu\text{C}$ are attached to the two ends of a massless and rigid uniform non-conducting rod of length $50 \text{ cm}$. This arrangement is held in a uniform electric field of $12.1 \text{ N/C}$,such that the rod makes a very small angle with the field direction. If the rod is set free,the minimum time needed for the rod to become parallel to the direction of the electric field is ................ seconds.

$A$ point electric dipole placed at the origin has a potential given by $V(r, \theta) = \frac{p \cos \theta}{4 \pi \varepsilon_0 r^2}$,where $\theta$ is the angle made by the position vector with the direction of the dipole. Then,

Mention the direction of the electric dipole moment. Write the $SI$ unit of the electric dipole moment.