$A$ particle of mass $m$ and charge $q$ is accelerated through a potential difference of $V$ volt. Its energy is

The maximum electric field that can be held in air without producing ionization of air is $10^7\,V/m$. The maximum potential,therefore,to which a conducting sphere of radius $0.10\,m$ can be charged in air is:

Two thin concentric hollow conducting spheres of radii $R_1$ and $R_2$ bear charges $Q_1$ and $Q_2$ respectively. If $R_1 < R_2$,then the potential of a point at a distance $r$ from the centre $(R_1 < r < R_2)$ is

$A$ 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:

Which of the following correctly represents the variation of electric potential $(V)$ of a charged spherical conductor of radius $(R)$ with radial distance $(r)$ from the centre?

Two tiny spheres carrying charges $1.8 \mu C$ and $2.8 \mu C$ are located $40 \ cm$ apart. The potential at the mid-point of the line joining the two charges is: