If a $10 \mu C$ charge exists at the centre of a square,the work done in moving a $2 \mu C$ point charge from corner $A$ to corner $B$ of a square $ABCD$ is

Which physical quantities are represented by $X$ and $Y$ in the given graph? ($Y$ represents the first quantity.)

Two equal positive charges each of value $q$ are placed at points $A$ and $B$, where $AB = 3x$. A third charge $-3q$ is placed at point $C$ at a distance $x$ from $A$ on the line segment $AB$. The potential energy of the system is nearly ($\epsilon_0$ = permittivity of free space).

Six charges $+q, -q, +q, -q, +q$ and $-q$ are fixed at the corners of a hexagon of side $d$ as shown in the figure. The work done in bringing a charge $q_0$ to the centre of the hexagon from infinity is: ($\varepsilon_0$ = permittivity of free space)

What is the electric potential at point $A$ due to the given charges?

Two identical thin rings each of radius $R \text{ m}$ are kept on the same axis at a distance of $R \text{ m}$ apart. If the charges on them are $10 \text{ C}$ and $5 \text{ C}$ respectively,calculate the work done in moving a charge '$q$' coulomb from the centre of one ring to that of another.