A charged particle with charge $q$ and mass $m$ starts with an initial kinetic energy $K$ at the centre of a uniformly charged spherical region of total charge $Q$ and radius $R$. Charges $q$ and $Q$ have opposite signs. The spherically charged region is not free to move and kinetic energy $K$ is just sufficient for the charge particle to reach boundary of the spherical charge. How much time does it take the particle to reach the boundary of the region?
$\sqrt[\pi ]{{\frac{{4\pi {\varepsilon _o}m{R^3}}}{{qQ}}}}$
$\sqrt[{\frac{\pi }{2}}]{{\frac{{4\pi {\varepsilon _o}m{R^3}}}{{qQ}}}}$
$\sqrt[{\frac{\pi }{4}}]{{\frac{{4\pi {\varepsilon _o}m{R^3}}}{{qQ}}}}$
None of the above.
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.)
Angle between equipotential surface and lines of force is.......$^o$
A charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium, if $q$ is equal to
The work done in placing a charge of $8 \times 10^{-18}$ coulomb on a condenser of capacity $100\, micro-farad$ is
There is a square gaussian surface placed in $y-z$ plane. Its axis is along $x-$ axis and centre is at origin. Two identical charges, each $Q$, are placed at point $(a, 0, 0)$ and $(-a, 0, 0)$. Each side length of square is $2a$ then electric flux passing through the square is