Consider a system of three charges $\frac{\mathrm{q}}{3}, \frac{\mathrm{q}}{3}$ and $-\frac{2 \mathrm{q}}{3}$ placed at points $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$, respectively, as shown in the figure,

Take $\mathrm{O}$ to be the centre of the circle of radius $\mathrm{R}$ and angle $\mathrm{CAB}=60^{\circ}$

Figure:$Image$ 

222758-q

  • [IIT 2008]
  • A

    The electric field at point $O$ is $\frac{\mathrm{q}}{8 \pi \varepsilon_0 \mathrm{R}^2}$ directed along the negative $\mathrm{x}$-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 $\mathrm{O}$ is $\frac{\mathrm{q}}{12 \pi \varepsilon_0 \mathrm{R}}$

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