A charge $Q$ is divided into two parts of $q$ and $Q - q$. If the coulomb repulsion between them when they are separated is to be maximum, the ratio of $\frac{Q}{q}$ should be
$2$
$0.5$
$4$
$0.25$
In the figure a potential of $+1200\, V$ is given to point $A$ and point $B$ is earthed, what is the potential at the point $P$ ?......$V$
Find capacitance across $AB$
Two point charges $+8q$ and $-2q$ are located at $x = 0$ and $x = L$ respectively. The location of a point on the $x-$ axis at which net electric field due to these two point charges is zero, is
Charge $q$ is uniformly distributed over a thin half ring of radius $R$. The electric field at the centre of the ring is
Three charges $4q,\,Q$ and $q$ are in a straight line in the position of $0$, $l/2$ and $l$ respectively. The resultant force on $q$ will be zero, if $Q = $