Which of these materials is an electrical insulator?
An electrostatic air purifier is used to remove dust from a room.
The diagram below shows a simplified model of the purifier.
The control unit applies a high voltage between Plate A and Plate B, causing Plate A to become negatively charged and Plate B to become positively charged.
Use the idea of charge movement to explain how Plate A becomes negatively charged and Plate B becomes positively charged.
Suggest why neutral dust particles are attracted to the negatively charged Plate A.
A student charges a plastic comb by rubbing it. When they bring the charged comb close to a thin stream of water running from a tap, the stream of water is deflected towards the comb.
Suggest why the stream of water is deflected.
