An electric dipole is placed at an angle of $30^\circ$ with an electric field intensity of $2 \times 10^5 \, \text{NC}^{-1}$. It experiences a torque equal to $4 \, \text{Nm}$. The charge on the dipole,if the dipole length is $2 \, \text{cm}$,is:

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:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The potential $(V)$ at any axial point, at $2 \ m$ distance $(r)$ from the centre of the dipole of dipole moment vector $\vec{P}$ of magnitude $4 \times 10^{-6} \ C \ m$, is $\pm 9 \times 10^3 \ V$.
(Take $\frac{1}{4 \pi \epsilon_0} = 9 \times 10^9 \ SI$ units)
Reason $R$: $V = \pm \frac{1}{4 \pi \epsilon_0} \frac{P}{r^2}$, where $r$ is the distance of any axial point, situated at $2 \ m$ from the centre of the dipole.
In the light of the above statements, choose the correct answer from the options given below:

In the case of the dimensions of electric field and electric dipole moment,the power of mass is respectively:

Three charges $q, -2q$ and $q$ are placed at $(x=0, y=a, z=0)$,$(x=0, y=0, z=0)$ and $(x=a, y=0, z=0)$ respectively. What is the resultant electric dipole moment?

The electric field due to a short electric dipole at a distance $r$ on the axial line from its mid-point is $x$ times the electric field at a distance $2r$ on the equatorial line from the mid-point of the dipole. Then,the value of $x$ is