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

Question

In a certain charge distribution, all points having zero potential can be joined by a circle an S. Points inside S have positive potential points outside S have negative potential. A positive charge, which is free to move, is placed inside S: (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

Tardigrade Admin · Accepted Answer

A free positive charge can move from higher (positive) potential to lower (negative) potential. Hence, it must cross S at some time.

Q. In a certain charge distribution, all points having zero potential can be joined by a circle an $S$ . Points inside $S$ have positive potential points outside $S$ have negative potential. $A$ positive charge, which is free to move, is placed inside $S$ :

it will remain in equilibrium

it can move inside S, but it cannot cross S

it must cross S at some time

it may move, but will ultimately return to its starting point

A free positive charge can move from higher (positive) potential to lower (negative) potential.
Hence, it must cross $S$ at some time.

Q. In a certain charge distribution, all points having zero potential can be joined by a circle an S. Points inside S have positive potential points outside S have negative potential. A positive charge, which is free to move, is placed inside S: