electrical insulators don't conduct charge well- so a current can't flow.(e.g. plastic and rubber)
Insulating Materials and friction:
When two insulating materials are rubbed together, the electrons will move from one to the other. This leaves a positive electrostatic charge on one and a negative electrostatic charge on the other; the way in which the electrons are transferred depends on the two materials. Then the electrically charged object attracts small objects placed near them. Examples of this are polyethene, glass and acetete rods.
Loss and gain of Electrons:
The positive charges of the material never moves, only the electrons.
There are forced of attraction between unlike charges (-ve and +ve) and forces of repulsion between like charges (-ve and ve or +ve and +ve).
Electrostatic phenomena in terms of the movement of electrons:
As the electric charge builds up so does the voltage, sometimes causing a spark when trying to get to the earth.
Potential dangers of Electrostatic charges:
Lightning----> Electro static charge is generated by induction when ice particles and rain drops in the clouds collide. This creates a high voltage and a big spark.
Prevention: conductors on buildings prevent strikes by discharging the cloud above or carries it safely to the ground.
Fuel-filling----> As fuel pours out of the filler pipe, static can build up, this can lead to a spark. Prevention: make the nozzles out of metal so that the charge is conducted away, instead of building up
Uses of electrostatic charge:
- removes dust from smoke of coal-fired power stations
- photocopiers and inkjet printers use it to put ink in the right place
- filter: vacuums and air --> responsible for effectiveness
Photocopier:
- high voltage wire charges drum
- drum is charged evenly
- light removes charge from parts that are not be printed
- charged parts attract toner particles
- toner rolled onto paper
- toner melted onto paper by heating
Information in bold italics are for paper 2
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