An oil drop carries six electronic charges, has a mass of $1.6 \times 10^{-12} g$ and falls with a terminal velocity in air. The magnitude of vertical electrical electric field required to make the drop move upward with the same speed as was formely moving is ........$kN/C$
$16.3$
$32.7$
$98$
None of the above
Write equation of electric field by point charge. How does it depend on distance ?
A cube of side $'a'$ has point charges $+Q$ located at each of its vertices except at the origin where the charge is $- Q$. The electric field at the centre of cube is
Two point charges $Q$ and $-3Q$ are placed at some distance apart. If the electric field at the location of $Q$ is $E$ then at the locality of $ - 3Q$, it is
In the given figure distance of the point from $A$ where the electric field is zero is......$cm$
A positively charged ball hangs from a silk thread. We put a positive test charge ${q_0}$ at a point and measure $F/{q_0}$, then it can be predicted that the electric field strength $E$