If a charge is shifted from a low potential region to a high potential region,the electric potential energy

Let $V_1$ be the potential at the center of a square of side $1 \ m$ when the charges at the $4$ corners are $2 \ C$ each. If the same charges are placed at the corners of a square of side $2 \ m$,then the potential at the center of this square is $V_2$. The value of $\frac{V_2}{V_1}$ is

Particle $A$ has a charge of $+q$ and particle $B$ has a charge of $+4q$. Both particles have the same mass. If they are released from rest under the same electric potential difference,what is the ratio of their speeds $V_A / V_B$?

For a point charge,the electric potential and electric field at a given point are $600 \, V$ and $200 \, N/C$ respectively. The magnitude of the point charge is ......... $\mu C$.

Along the $x$-axis,three charges $\frac{q}{2}, -q$ and $\frac{q}{2}$ are placed at $x=0, x=a$ and $x=2a$ respectively. The resultant electric potential at a point $P$ located at a distance $r$ from the charge $-q$ $(r > a)$ is ($\varepsilon_0$ is the permittivity of free space):

An electric dipole is placed as shown in the figure. The electric potential (in $10^2 \ V$) at point $P$ due to the dipole is ($\epsilon_0 =$ permittivity of free space and $\frac{1}{4 \pi \epsilon_0} = K$):