If a charge $q$ is placed at the centre of the line joining two equal charges $Q$ such that the system is in equilibrium then the value of $q$ is (1) $Q/2$ (2) $-Q/2$ (3) $Q/4$ (4) $-Q/4$
If a charge $q$ is placed at the centre of the line joining two equal charges $Q$ such that the system is in equilibrium then the value of $q$ is\\
(1) $Q/2$\\
(2) $-Q/2$\\
(3) $Q/4$\\
(4) $-Q/4$