Vicky combs her hair with a plastic hair comb - Edexcel - GCSE Physics - Question 6 - 2012 - Paper 1

Vicky's hair becomes positively charged due to friction between the comb and her hair. When she combs her hair, electrons move from the hair to the comb. This transfer of electrons causes the hair to lose some of its electrons, resulting in a positive charge overall as it now has more protons than electrons.

On the diagram, the negatively charged area of the foil can be indicated on the side facing the comb because the comb, carrying a negative charge, would repel the negative charges in the foil. Thus, an arrow or label showing the area of the foil that is not in contact with the comb would effectively indicate where the foil is negatively charged.

The metal comb does not pick up the metal foil because both the comb and the foil are neutral or have similar charges. Therefore, there is no attractive force between them to allow the foil to be picked up.

Using an electrostatic paint sprayer provides several benefits. Firstly, because the paint particles are negatively charged, they will repel each other as they leave the nozzle, which helps create an even spray pattern with less clumping. Additionally, the charged particles are attracted to the metal object, ensuring more paint adheres to the surface rather than missing it, reducing waste and improving coverage efficiency. This method also allows for better control in application, minimizing overspray and ensuring even distribution of paint.