ELECTROSTATICS Flashcards
(12 cards)
List 4 conductors
Copper
Tin
Aluminium
Steel
List 4 insulators
Plastic
Glass
Rubber
Wood
How does an inkjet printer use static electricity?
1)inkjet printers use inkjets to direct a fine jet of ink drops onto paper
2) each drop of ink is given a charge
3) as it falls between a pair of deflecting plates, electrostatic forces direct it to the correct position
4) the charges of the plates changes hundreds of times each second so drops always fall into different positions
How are electrostatics used in spray painting/ insecticide spraying
1) the metal spray nozzle charges each drop of paint as it emerges from the spray gun
2) as all drops carry the same charge, they repel each other and spread out to form a thin spray
3) the object is attached to a wire connecting it to the opposite charge
4) the paint drops are then attracted to the object surface
5) the paint can reach even corners that are usually hard to reach
How are electrostatic used in photocopiers?
1) turning drum is charged
2) image is projected onto positive plate, as charge stays only where the image is dark
3) a negatively charged black toner is then applied to the plate and sticks to the positively charged areas
4)blank paper is then pressed against toner image
5) the paper is heated to melt toner image and form a permanent image on paper
How are electrostatics used in industrial plants?
1) as the smoke rises up the chimney, it passes through a highly charged mesh of wires
2) as they pass, the ash and dust become negatively charged
3) these charged particles are then attracted and stick to earthed, metal plates higher up the chimney
4) allow cleaner smoke to rise into the atmosphere
Dangers of static electricity:
1) fuelling aircraft’s
2)SPARKING which can cause a fire
3) risk of electrocution/ shock
How are fuelling aircraft’s/vehicles a danger?
1) when aircraft’s are flying, the friction can cause them to become charged
2) when they reach the ground, their is possibility of sparking as charges escape to the earth
3) if this happens during refuelling, it can cause an explosion
3) the fuel running very fast through pipes, can also cause the fuel to become charged
4)which could cause a spark, and therefore an explosion
How to prevent dangers when fuelling aircraft’s/vehicles:
1) earth the plane with a conductor “bonding line” wire
2) which provides an easier route for the charge of lower resistance,
3)which allows the built up charge to flow to the earth
Explain how the rod and cloth work
As the rod and cloth are both INSULATING MATERIALS
When rubbed together, electrons are transferred from one material to the other (ex: from the rod to the cloth)
As the cloth gains electrons, it becomes negatively charged, and opposite for the rod
The opposite forces attract, and the rod becomes attracted to the cloth
As they are both now charged, they can also attract other materials
Explain how a balloon sticks to the wall
When the balloon is rubbed against another insulating material,
There are electrons transferred from one to the other (ex: the ballon gains electrons)
This causes the balloon to become charged (negatively if electrons are transferred)
As the balloon draws nearer to a neutral object (ex: a wall)
The similar positive charges repel, and the electrons in the wall repel away
Leaving a surplus of positive charges at the wall surface, causing a temporarily induced positive charge of the surface
Electrostatic forces of attraction causes the negatively charged balloon to stick to the temporarily positively charged wall surface.
CORE PRACTICAL: investigating how insulating materials can become charged by friction
S- time spent rubbing the cloth, using the same type of cloth, distance from paperclips, using same length of rods
C- rods of different material (acetate, polythene, wood, acrylic)
R-repeat
E- wooden stand + ruler
A- count the number of pieces of paper picked up by each rod
M- the amount of pieces of paper picked up by each rod
S- ensure no draft in room, rub each rod for a long period of time to produce more visible results,
