Equal charges $q$ are placed at the vertices $A$ and $B$ of an equilateral triangle $ABC$ of side $a$. The magnitude of electric field at the point $C$ is

The insulation property of air breaks down at $E = 3 \times {10^6}$ $volt\,/\,metre$. The maximum charge that can be given to a sphere of diameter $5\,m$ is approximately (in coulombs)

Find the electric field at point $P$ (as shown in figure) on the perpendicular bisector of a uniformly charged thin wire of length $L$ carrying a charge $Q.$ The distance of the point $P$ from the centre of the rod is $a=\frac{\sqrt{3}}{2} L$.

The intensity of electric field required to balance a proton of mass $1.7 \times {10^{ – 27}} kg$ and charge $1.6 \times {10^{ – 19}} C$ is nearly

A charged particle of mass $5 \times {10^{ – 5}}\,kg$ is held stationary in space by placing it in an electric field of strength ${10^7}\,N{C^{ – 1}}$ directed vertically downwards. The charge on the particle is