Energy of electrons can be increased by allowing them

$A$ charge $Q$ is uniformly distributed over a rod $AB$ of length $L$ as shown in the figure. The electric potential at point $O$,which is at a distance $L$ from end $A$,is:

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

The radius of a soap bubble whose potential is $16\,V$ is doubled. The new potential of the bubble will be.....$V$

The figure shows a solid hemisphere with a charge of $5 \ nC$ distributed uniformly throughout its volume. The hemisphere lies on a plane and point $P$ is located on this plane,along a radial line from the center of curvature at a distance of $15 \ cm$. The electric potential at point $P$ due to the hemisphere is ..... $V$.

An electron enters a high potential region $V_2$ from a lower potential region $V_1$. What happens to its velocity?