An empty thick conducting shell of inner radius $a$ and outer radius $b$ is shown in figure.If it is observed that the inner face of the shell carries a uniform charge density $-\sigma$ and the surface carries a uniform charge density $ '\sigma '$

If another point charge $q_B$ is also placed at a distance $c ( > b) $ the center of shell, then choose the correct statements 

115-947

  • A

    force experienced by charge $A$ is $\frac{{\sigma {q_A}{b^2}}}{{{\varepsilon _0}{c^2}}}$

  • B

    force experienced by charge $A$ is zero

  • C

    The force experienced by charge $B$ is $\frac{{\sigma {q_B}{b^2}}}{{{\varepsilon _0}{c^2}}}$

  • D

    The force experienced by charge $B$ is $\frac{{k{q_A}{q_B}}}{{{c^2}}}$

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