Charges $Q$ are placed at each corner of a square of side $a$. How much work is required to remove a charge $-Q$ from the center of the square and move it to infinity?

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

Define electron volt and convert it into Joule unit.

State which of the following is correct.

An electron (charge = $1.6 \times 10^{-19} \text{ C}$) is accelerated through a potential of $100,000 \text{ V}$. The energy acquired by the electron is:

$A$ charge $+q$ is fixed at each of the points $x = x_0, x = 3x_0, x = 5x_0, \dots$ up to $\infty$ on the $X$-axis and a charge $-q$ is fixed at each of the points $x = 2x_0, x = 4x_0, x = 6x_0, \dots$ up to $\infty$. Here $x_0$ is a positive constant. Taking the potential at a point due to a charge $Q$ at a distance $r$ from it to be $\frac{Q}{4\pi\varepsilon_0 r}$,find the potential at the origin due to the above system of charges.