When an insulating acetate rod is rubbed with a dry silk cloth, the acetate rod becomes positively charged.

Identify the two correct statements from the list below:

• Statement A: Negatively charged electrons are transferred from the acetate rod to the silk cloth.
• Statement B: Positively charged protons are transferred from the silk cloth to the acetate rod.
• Statement C: The silk cloth becomes negatively charged.
• Statement D: The acetate rod gains positive protons to become positively charged.

When dry flour particles flow at high speed down a metal chute in a food packaging plant, electrostatic charge can build up.

Give a reason why a build-up of electrostatic charge in this environment can be dangerous.

State how this build-up of electrostatic charge on the chute and machinery is prevented.

An electrostatic powder-coating system is used to coat a household appliance panel. As the fine plastic powder particles leave the nozzle, they gain a negative electrostatic charge and spread out in a wide cloud.

Draw on this

Explain, in terms of charges, why the powder particles spread out.