Helen has just had a shock. she got up from a plastic chair to open the door and got an electric shock when she touched the door handle.
i) How did she become charged?
ii) Why did she feel a shock when she touched the door handle?
Helen rubbed the chair as she stood up and that created a charge on her body opposite to the charge on the chair. She discharged to the door handle when she touched it and that created the shock.
As a note, some materials have a varying affinity for electrons, and can acquire a charge when rubbed with another material.
i) Helen became charged with static electricity when she got up from the plastic chair. Static electricity is created when two materials rub against each other, causing the transfer of electrons from one material to another. In this case, when Helen got up from the plastic chair, the movement caused friction between her clothes and the chair, resulting in the transfer of electrons between them. This transfer of electrons left both Helen and the plastic chair with an imbalance of positive and negative charges, causing Helen to become charged.
ii) Helen felt a shock when she touched the door handle because there was a difference in electrical charge between her and the door handle. When Helen became charged with static electricity, she acquired an excess of either positive or negative charges. Similarly, the door handle may have become charged with the opposite charge. When Helen reached out to touch the door handle, the charges on her body repelled the charges on the door handle, leading to a buildup of static electricity between them. This buildup of charge created a potential difference, and when Helen touched the door handle, the excess charges quickly balanced out, resulting in an electric shock. The shock is the sudden flow of electrons between the charged objects to equalize their charges.