Three equal charges are placed at the corners of an equilateral triangle. Which of the graphs below correctly depicts the equally-spaced equipotential surfaces in the plane of the triangle? (All graphs have the same scale.)

$A$ non-conducting ring of radius $0.5\,m$ carries a total charge of $1.11 \times 10^{-10}\,C$ distributed non-uniformly on its circumference,producing an electric field $\vec{E}$ everywhere in space. The value of the line integral $\int_{l = \infty }^{l = 0} { - \vec{E} \cdot d\vec{l} }$ (where $l = 0$ is the centre of the ring) in volts is:

The work done in carrying a charge of $5\,\mu C$ from a point $A$ to a point $B$ in an electric field is $10\,mJ$. The potential difference $(V_B - V_A)$ is then

The figure shows a positively charged infinite wire. $A$ particle of charge $q = 2 \, C$ moves from point $A$ to $B$ with constant speed. (Given linear charge density on the wire is $\lambda = 4 \pi \varepsilon_0$)

In a uniform electric field,the potential is $10 \ V$ at the origin of coordinates,and $8 \ V$ at each of the points $(1, 0, 0), (0, 1, 0)$ and $(0, 0, 1)$. The potential at the point $(1, 1, 1)$ will be....$V$

The unit of the physical quantity obtained by the line integral of the electric field is . . . . . . .