Question

Point charges `+4q, -q` are kept on the `x`-axis at points `x=0,x=a` and `X=2a` respectively, then
A. Only `q` is in stable equilibrium
B. None of the charges are in equilibrium
C. All the charges are in unstable equilibrium
D. All the charges are in stable equlibrium

Answer 1

Correct Answer - c
Force on each charge is Zero. But if any of the charge is displaced, the net force starts acting on all of them.