two point charge +q and +9q are seperated by a distance of 16 cm. at what point between these charges should a third charge Q be placed so that it remains in equilibrium .

Third charge must be placed 4 cm away from q charge.As the charges are in equilibrium and charges have same nature .so the point lie between these charges at x distance from q charqeMagnitude of F1=magnitude of F2(k×q×qo)÷x^2=(k×9q×qo)%(16-x)^2