Static electricity Flashcards
What does static mean?
stationary
What is friction?
the force that opposes motion between two surfaces moving together
What is an electron?
a small negatively charged particle orbiting the nucleus of an atom
A charge can be . . .
positive or negative
What is a static charge?
a charge that can’t move
What is repulsion?
when two forces push against each other
What is attraction?
when two forces pull each other together
What is a conductor?
a material that will allow the flow of electricity through it
What is an insulator?
a material that will not allow the flow of electricity through it
How is a spark formed?
its formed as electrons jump from one material to another
What is potential difference?
The energy transferred per unit charge
What is an Earth wire?
a metal connected to an object that will safely conduct any build of static charge to the ground
What is an electric field?
the region around a charge where another charge will feel a force
What are the two rules for interaction of charges?
- opposite charges attract
- same charges repel
What is static electricity?
a build up of static charge on the surface of an object
How is static electricity produced?
when two insulators are rubbed together, friction causes electrons to be stripped from one material onto the other
What happens when a static electricity is produced? (2 things)
the material that lost electrons will become positively charged
the material that gained electrons will become negatively charged
Can metals have a static charge?
if they are insulated from the ground a charge can be placed on a metal
(it will spread evenly over the surface)
What are the four uses of static electricity?
- paint spraying
- insecticide spraying
- photocopiers
- electrostatic smoke precipitators
How do paint sprayers work?
- paint particles are given the same charge from a positively charged electron in the spray nozzle
- particles all have the same charge so repel each other
- this results in a fine mist
Ho do photocopiers work?
- photo-conducting drum is positively charges until light falls on it
- light is reflected off of paper onto the drum
- areas of black don’t reflect so these areas stay charged
- black toner sticks to the charged areas (opposite charges attract)
- paper is heated so that toner sticks to the paper permanently
How do electrostatic smoke precipitators work?
- smoke particles move through metal grid and are given a negative charge
- smoke particles have a different charge to the metal plates inside the chimney
- smoke particles are attracted to the metal plates, and separated from the clean waste gas
How do insecticide sprayers work?
- each droplet is given the same charge
- the drops repel each other, so they spread evenly
- droplets are attracted to the Earth (opposite charges attract)
- means particles fall fast and are less likely to get blown away
What do the field lines show about the force in an electric field?
field lines show the direction of the force
lines point away from a positive charge and towards a negative charge
