Answer: The paper prices fall off due to repulsive forces.
Explanation: When an electrified or charged object is brought near an uncharged object, it causes the electrons of the uncharged object to move as electrons are free movable particles. The electron leave behind the atoms. The uncharged object becomes ionized.
Here the pieces of paper may fall off because it becomes de-ionized by surrounding air particles. While the pieces are attached to the rod, surrounding air particles may provide or take away electrons and make the pieces become neutral again