question_answer

In a certain charge distribution, all points having zero potential can be joined by a circle S. Points inside S have positive potential and points outside S have negative potential. A positive charge, which is free to move, is placed inside S                                                                      [DPMT 2004]

A)                    It will remain in equilibrium

B)                    It can move inside S, but it cannot cross S

C)                    It must cross S at some time

D)            It may move, but will ultimately return to its starting point