Question. Three charged particles are collinear and are in equilibrium, then
a) all the charged particles have the same polarity
b) the equilibrium in unstable
c) all the charged particles cannot have the same polarity
d) both (a) and (c ) are correct
Answer: d) both (a) and (c ) are correct
If a charged particle is in equilibrium under electrostatic force, then that particle never be in stable equilibrium. Hence option B is correct.
Since all charges are in equilibrium, net force an any one of the charges are in equilibrium,so net force an any one of charges should be zero-for this two equal and opposite forces will act on any charge. Hence option C is correct.