In Millikan's experiment, an oil drop having charge $q$ gets stationary on applying a potential difference $V$ in between two plates separated by a distance $d$. The weight of the drop is
$\frac{q}{{Vd}}$
$q\frac{d}{V}$
$q\,Vd$
$q\frac{V}{d}$
Electric field at a place is $\overrightarrow {E\,} = {E_0}\hat i\,V/m$ . A particle of charge $+q_0$ moves from point $A$ to $B$ along a circular path find work done in this motion by electric field
A unit positive point charge of mass $m$ is projected with a velocity $V$ inside the tunnel as shown. The tunnel has been made inside a uniformly charged non conducting sphere. The minimum velocity with which the point charge should be projected such it can it reach the opposite end of the tunnel, is equal to
Potential atapoint $A$ is $3 $ $ volt$ and atapoint $B$ is $7$ $volt$,an electron is moving towards $A$ from $B.$
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
When three electric dipoles are near each other, they each experience the electric field of the other two, and the three dipole system has a certain potential energy. Figure below shows three arrangements $(1)$ , $(2)$ and $(3)$ in which three electric dipoles are side by side. All three dipoles have the same magnitude of electric dipole moment, and the spacings between adjacent dipoles are identical. If $U_1$ , $U_2$ and $U_3$ are potential energies of the arrangements $(1)$ , $(2)$ and $(3)$ respectively then