In a certain region of space,the electric field is along the $z$-direction throughout. The magnitude of the electric field is,however,not constant but increases uniformly along the positive $z$-direction at the rate of $10^{5} \; N \, C^{-1}$ per meter. What are the force and torque experienced by a system having a total dipole moment equal to $10^{-7} \; C \, m$ in the negative $z$-direction?

The electric field due to an electric dipole at a distance $r$ from its centre in the axial position is $E$. If the dipole is rotated through an angle of $90^{\circ}$ about its perpendicular axis,the electric field at the same point will be

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:

Two point charges $-q$ and $+q$ are placed at a distance of $L$,as shown in the figure. The magnitude of electric field intensity at a distance $R$ $(R \gg L)$ varies as:

The potential at a point due to an electric dipole will be maximum and minimum when the angles between the axis of the dipole and the line joining the point to the dipole are respectively:

The angle between the electric dipole moment of a dipole and the electric field strength due to it on the equatorial line is (in $^{\circ}$)