Question

Why does the ball repel as it touches the rod​

Answer 1

Electrons from the rod move to the pith ball giving the pith ball an excess of negatively charged electrons (a net negative charge). This is known as electrostatic conduction. Now that both the rod and the pith ball have the same negative charge, they repel each other.

Answer 2

when a charged rod is brought close to the pith balls, their charges polarize. if they find in contact with the charged rod, they can inherit the same sign charge. since like charges repel. when similarly charged, the pith balls behave like siblings and refuse to touch each other.

THANK YOU