What is a point dipole?

The electric potential at a point on the axis of an electric dipole is proportional to $[r=$ distance between the centre of the electric dipole and the point].

Charges $-q$ and $+q$ located at $A$ and $B$,respectively,constitute an electric dipole. Distance $AB = 2a$,$O$ is the midpoint of the dipole and $OP$ is perpendicular to $AB$. $A$ charge $Q$ is placed at $P$ where $OP = y$ and $y >> 2a$. The charge $Q$ experiences an electrostatic force $F$. If $Q$ is now moved along the equatorial line to $P'$ such that $OP' = \frac{y}{3}$,the force on $Q$ will be close to: $\left( \frac{y}{3} >> 2a \right)$

Three charges $+2q$,$+3q$,and $-4q$ are situated at $(0, -3a)$,$(2a, 0)$,and $(-2a, 0)$ respectively in the $xy$ plane. The resultant dipole moment about the origin is . . . . . .

An electric dipole of moment $\vec{P}$ is placed in a uniform electric field $\vec{E}$ such that $\vec{P}$ points along $\vec{E}$. If the dipole is slightly rotated about an axis perpendicular to the plane containing $\vec{E}$ and $\vec{P}$ and passing through the centre of the dipole, the dipole executes simple harmonic motion. Consider $I$ to be the moment of inertia of the dipole about the axis of rotation. What is the time period of such oscillation?

Write the equation for the electric field produced by an electric dipole at a point on its axial line,given the condition $r >> a$.