Electrostatics Flashcards
What materials are needed for something to become charged?
Insulating materials
What is it called when something become charged
Electrostatic charge
If one bodies is negatively charged and the other positively what will they do?
Attract each other
When a polythene rod is rubbed with a woollen cloth electrons move from the cloth to the polythene rod. What charge does the rod have?
Negative, as electrons have a negative charge
When acetate is rub against a woollen cloth electrons move on the cloth. The rod become positively charged. Why?
It’s lost negatively charged electrons
Negative charge mean extra electrons. What does positive charge mean?
Lack of electrons
What are atoms or molecules that have become charged called?
Ions
How is soot and ash removed in power stations?
By a Electrostatic smoke precipitator
How is soot and ash removed in power stations?
By a Electrostatic smoke precipitator
What picks up smoke particles
A charged metal grid.
What happens inside smoke precipitators
Smoke particles pick up electrons from the grid and become negatively charged themselves from the negatively charged grid. The grid now repeals the negative smoke particles towards the chimney lining. Where they are attracted by largely positively charged collecting plates. The smoke particles lose charge on collecting particles and collect together at the bottom of the chimney.
What are photoconductors
Things that conduct electricity in the light
How is a spark caused?
When a static charge on an object is large, electrons may jump across the gap from the charged gap to a nearby conductor.
What is earthing?
It involves connecting a charged body to a metal spike or place in the ground so it’s discharged, and its potential remains close to zero.
What things are earthed?
Petrol storage tanks and aircrafts are earthed.
What do conducting tails do?
Cars are fit with conducting tails to prevent build up of charge. As the car moves electrons are transferred from the ground to the car. Discharging reduces risks of unpleasant spark, when refuelled.
What happens to aircraft tyres
There is friction between aircraft tyres and the runway. To reduce build up of charge they’re made of special rubber that conducts electricity, so charge goes straight to the earth.
How can fabrics be anti static?
Buy anti static liquids, that conduct electricity and prevent build up of charge. Fabric conditioners contain a chemical that coats clothing with a layer that conducts charge.
Paint sprays
Particles become charged as they’re being sprayed. The object has an opposite charge so that the paint attracts to it. Paint particles repel as the have same charge, creates finer spray.
What do defibrillators do?
They restart a persons heart, when it’s stopped beating. Charge passes through paddles to the patients chest. Paddles have insulating handles to stop others from getting electrostatic-ly shocked.
How do printers work?
Laser printer has a drum which becomes negatively charged where laser shines on it. Toner is negatively charged so sticks to the drum that’s positively charged, then image is transferred.
