The electric field $\vec{E}$ at a point at a distance $r$ from the axis of a dipole is given by:

Write the expression for the torque experienced by an electric dipole placed in a uniform electric field.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: If an electric dipole of dipole moment $30 \times 10^{-5} \, Cm$ is enclosed by a closed surface,the net flux coming out of the surface will be zero.
Reason $R$: An electric dipole consists of two equal and opposite charges.
In the light of the above statements,choose the correct answer from the options given below:

An electric dipole with dipole moment $p$ is placed with its axis at $30^{\circ}$ to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is

Three point charges $+q, -2q$ and $+q$ are placed at points $(x = 0, y = a, z = 0)$,$(x = 0, y = 0, z = 0)$ and $(x = a, y = 0, z = 0)$ respectively. The magnitude and direction of the electric dipole moment vector of this system are:

$A$ neutral ammonia $(NH_3)$ molecule in its vapour state has an electric dipole moment of magnitude $5 \times 10^{-30} \ C \cdot m$. How far apart are the molecule's centres of positive and negative charge?