Electron volt is a unit of

In the following diagram, the work done in moving a point charge from point $P$ to points $A, B$ and $C$ is $W_A, W_B$ and $W_C$ respectively. If there is no charge nearby, then:

There is a uniform electrostatic field in a region. The potential at various points on a small sphere centered at $P$,in the region,is found to vary between the limits $589.0\,V$ to $589.8\,V$. What is the potential at a point on the sphere whose radius vector makes an angle of $60^o$ with the direction of the field (in $,V$)?

Consider a sphere of radius $R$ with uniform charge density and total charge $Q$. The electrostatic potential distribution inside the sphere is given by $V(r) = \frac{Q}{4 \pi \varepsilon_{0} R} \left( a + b(r/R)^c \right)$. Note that the zero of potential is at infinity. The values of $(a, b, c)$ are

Three charges,each $+q$,are placed at the corners of an isosceles triangle $ABC$ with sides $BC = AC = 2a$. $D$ and $E$ are the midpoints of $BC$ and $AC$,respectively. The work done in taking a charge $Q$ from $D$ to $E$ is

Three equal electric charges,each of magnitude $q$,are placed at the vertices of an equilateral triangle of side length $L$. The electrostatic potential energy of the system is: