A particle of mass $m$ having negative charge $q$ move along an ellipse around a fixed positive charge $Q$ so that its maximum and minimum distances from fixed charge are equal to $r_1$ and $r_2$ respectively. The angular momentum $L$ of this particle is
$\sqrt \frac{mr_1r_2Qq}{\pi\varepsilon_0(r_1 +r_2)}$
$\sqrt \frac{mr_1r_2Qq}{2\pi\varepsilon_0(r_1 +r_2)}$
$\sqrt \frac{mr_1r_2Qq}{3\pi\varepsilon_0(r_1 +r_2)}$
$\sqrt \frac{mr_1r_2Qq}{4\pi\varepsilon_0(r_1 +r_2)}$
Three identical small electric dipoles are arranged parallel to each other at equal separation a as shown in the figure. Their total interaction energy is $U$. Now one of the end dipole is gradually reversed, how much work is done by the electric forces.
Explain electric potential energy. Show that the sum of kinetic energy and electric potential energy remains constant.
The diagram shows three infinitely long uniform line charges placed on the $X, Y $ and $Z$ axis. The work done in moving a unit positive charge from $(1, 1, 1) $ to $(0, 1, 1) $ is equal to
Charges $-q,\, q,\,q$ are placed at the vertices $A$, $B$, $C$ respectively of an equilateral triangle of side $'a'$ as shown in the figure. If charge $-q$ is released keeping remaining two charges fixed, then the kinetic energy of charge $(-q)$ at the instant when it passes through the mid point $M$ of side $BC$ is
A particle has a mass $400$ times than that of the electron and charge is double than that of a electron. It is accelerated by $5\,V$ of potential difference. Initially the particle was at rest, then its final kinetic energy will be......$eV$