When a glass rod is rubbed with a silk cloth, the glass rod becomes positively charged.

Identify the two correct statements from the list below:

• Statement A: Negatively charged electrons move from the glass rod onto the silk cloth.
• Statement B: Positively charged protons move from the silk cloth onto the glass rod.
• Statement C: The silk cloth becomes negatively charged.
• Statement D: The glass rod gains protons to become positively charged.

When dry flour particles flow rapidly down a polymer-lined chute in a milling factory, electrostatic charge can build up.

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

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

An electrostatic crop sprayer is used to distribute pesticide onto crops. As the liquid pesticide droplets are forced through the nozzle, they gain an electrostatic charge and disperse into a wide, uniform cloud.

Draw on this

Explain, in terms of charges, why the pesticide droplets disperse into a wide cloud.