Consider a system of three charges $$\frac{q}{3}, \frac{q}{3}$$ and $$-\frac{2q}{3}$$ placed at points A, B and C, respectively, as shown in the figure. Take O to be the centre of the circle of radius R and angle $$CAB = 60^\circ$$

A

The electric field at point O is $$\frac{q}{8 \pi \varepsilon_0 R^2}$$ directed along the negative x-axis

B

The potential energy of the system is zero

C

The magnitude of the force between the charges at C and B is $$\frac{q^2}{54 \pi \varepsilon_0 R^2}$$

D

The potential at point O is $$\frac{q}{12 \pi \varepsilon_0 R}$$