Explain why when a polythene rod which has been rubbed with dry cloth is held high above small pieces of paper on the table, the pieces of paper jump up and down repeatedly between the table and the rod.
When a polythene rod is rubbed with a dry cloth, it becomes charged with static electricity. This static charge creates an electric field around the rod. When the charged rod is held above small pieces of paper on the table, the paper gets attracted to the rod due to the opposite charges. The paper jumps up and down repeatedly between the table and the rod because the attraction between the charged rod and the paper is stronger than the force of gravity pulling the paper down. This causes the paper to oscillate between the two opposing forces, creating a jumping effect.
